Home-made cannons, howitzers and mortars

[User Name]

I have recently made a 40mm steel cannon. it is 4 feet long and weights 35lbs without the carage. I use 100grams of blackpowder as a propellant and a steel 35mm by 35mm cylinder with a cotton sobot. the main barrel is made from 1/4" DOM (drawn over mandrel) tubing that has a psi rating of 45,000psi.

has anyone ever made and tested their own cannon, howitzer, or mortar? if so...give some specs about it and your results.

[NickSG]

Never made anything too fantastic, just a small golf ball cannon made from PVC pipe. Just 2 or 3 seconds worth of propane shot them well over 200 feet. Not that great though.

How much does you projectiles weigh? I image with 100 grams of BP any weight projectile would be damn powerful.

[User Name]

the projectile weighed um.........

i dont know but ill weigh it soon and post it. i would imagin about 7oz. and yes it was powerful as.......um......damn im tired sorry. i shot it at a huge boulder that was 300 yards away and i saw the impact. i missed the boulder by about 200 feet to the high right (i guess the cannon isnt acurate) but extremely powerful.

i would like to figure out how many joules of energy my projectiles have...anyone know the formula? ill just ask my chem. teacher. (shes retarded though i swear)

i have a chronograph and i chronoed the first shots out of the cannon...the average velocity was 782 feet per second (fps) figure the weight of projectile at 7oz.

thx

[Nihilist]

that's quite impressive, 782 fps, for a 7 oz projectile is quite a bit of energy. However, you should have searched before posting, as i'm quite sure information on this subject has been posted before.

[Axt]

Foot-pounds of energy is still the standard measurement for projectile weapons, therefore probably more relevant then joules (1 joule = 0.737562149 fp). 7oz at 782 = 4159fp

comparisons -
.22 = around 130fp
.308 = around 2625fp

Formula - Bullet weight (grains) x velocity (feet per second) squared / 450240 (constant)

[Flake2m]

I have managed to aquire a length of 50mm metal pipe. Since the walls are about 5mm thick, It shouldn't have a problem handling BP and perchlorate charges provided they aren't too large. To use this effectively I would want well designed ammo. I was think of using 40mm PVC pipe with an endcap that would be able to hold an HE charge but for blank firing/range testing it could just hold cement.

As you know the most difficult part of using an improvised cannon/mortar is loading them. You have to figure how much LE to use to make your projectile go so far or fast. My idea uses premade charges that are contained in toilet rolls. That way you can simply drop the charge into the barrel, then the ammo before aiming and firing it. This would reduce the reload time alot.

[User Name]

5mm walls are very thin. and your tube is pretty wide (50mm) be careful when testing. thankyou Axt for that formula and thankyou for complimenting my howitzer. the best thing about it, is that it isnt muzzle loading. i made a breach in the back out of a solid cylinder of hi tensil steel.

dont ever use PVC lol

Sch. 40 PVC psi rating = 300psi

DOM 1/4 wall steel (same size) = 45,000psi

[Anthony]

5mm thick walls should be ok for a mortar/grenade launcher. It doesn't require a very high chamber pressure to lob an object a few hundred yards.

[NickSG]

Yep. It only takes 1/2 teaspoon of black powder to launch a 1 pound object several hundred feet high.

BTW, there are about 7000 grains per pound, and about 450 per ounce. Your cannon is not far away (energy wise) from a .50 BMG, so I imagine it would be fun to shoot.

I made a 20mm cannon, but I forgot to add it in my first reply. It shot CO2 cannisters (18 or 19 mm), and its lift charge was 20 grams of black powder. I never shot it way out in the middle of nowwhere, but becuase it drove a CO2 cannister through a 16 guage steel plate, I think it could shoot at least 300 yards.

[User Name]

my cannon is based apon Robars main display .50 Mcbros is teamed up with robar to make .50's the coolest thing about my cannon (howitzer) is its double baffel muzzle break. it takes away probably 40% of the total recoil. at night its awsome!!
my next howitzer is going to be only a 32mm but shoot aluminum rounds at more than 2000fps. and oh yes, i will acheive 2000pfs! not with black powder obviouly.

ive been doing this for about 10 years now.
anyone can blow the living shit outa something, but it takes a real man to control that power and shoot a projectile acuratly at his neighbors BMW
(*ooops did i say that outloud*)

[NickSG]

I might try using NC as the lift charge in my cannon. I know its much more powerful than black powder, and I cant wait to see how it does in my cannon.

[FCUK]

If your looking for a source of pipes at whatever length/thickness. I suggest following site: http://www.pipelocater.com/filter.asp

[User Name]

Always use seamless Drawn Over Mandrel high carbon steel, or DOM seamless for short. This is the strongest tube of steel in the world and ANY size can be made for a reasonable price. (I see $90 as reasonable)

NC is great propellant if you have a strong cannon. nothing beats AN though. i used to have a mortar with only a 12" barrel but extremely thick walled. and i used to shoot huge 1gallon coffe cans full of cement hella far using APAN. Cool shit!

[kingspaz]

user name, you can't read this because zaibatsu has banned you for crimes in another thread. but just incase you can read it, i would have banned you for talking bullshit ;)

[xyz]

Before any newbies decide to try APAN as a propellant, DON'T use anything that detonates as a propellant unless you have designed the weapon to be disposable and will not be near it when it goes off.

[Efraim_barkbit]

The formula for calculating kinetic energy using SI units is: E = (m*v^2)/2
where E=kinetic energy (J), m=mass (kg), v=velocity (m/s)

For user name, his readings would first have to be changed to SI units:
7 oz=7*0,02835~0,198kg
782fps=782*0,3048~238,4m/s

E = (0,198*238,4^2)/2 ~ 5,63kJ

[keith]

No one has posted anything on this topic in a while and my post is similar to teh thread.....I am curently making a 2 foot long "cannon" (not really a cannon but w/e) that can fire a projectile at a speed>4000fps. Most rifles ie. (30-06) shoots a 165gr projectile at about 2800fps using smokeless gun powder containing nitrocellulose, nitroglycerin (very little amounts) and other stuff(not important). The closest Ive come to reaching my goal of 4000fps was with a small pistol sized cannon using acetone peroxide and ammonium nitrate for a propellant. As you can imagin, the gun broke. The barrel walls were only 1/4 inches thick BUT they didnt fully break! They only expanded from .65" to almost .73".
My next "cannon" will have twice as long of a barrel and a wall thickness of 1 inch. The bullet diameter will be .5". I am buying 440 stainless steel solid bars then machining them to my specs. I will use the same weight charge and ratios as before so I dont ruin this cannon as well.
If anyone has any idea of a propellant that has a VOD fast enough to acheive my goal yet will not damage the weapon it would be greatly appreciated.

[Blackhawk]

I would try something imilar to flash, but you simply can-not use anything that detonates, you will not be able to contain that kind of power. If you wan't to increase velocity use a slower burning LE charge with a large gas output and make the barrel VERY long, as burn velocities increase so does the stress on the gun, but you can make better use of the gas already being genarated.

[irish]

Keith,
Your APAN detonates, that is going to destroy your barrel no matter what it's made of or how thick it is. You can get rounds to 4000 fps with smokeless powder (you can get them up to at least 6000 fps if you go about it right, not easy but it's been done, I can't remember the caliber that was used) .
To get a .50 slug up to 4000 fps in a 4 foot barrel you will probably be best to go with a lot of whatever the fastest burning powder is you can get, pressure is obviously going to be massive. If you can make a longer barrel and use a slower powder (ie a long push up the barrel rather than a short shove) it would probably be better.
Whatever you end up doing I recommend you stick to nitrocellulose based powders.

[keith]

I disagree with what you said abou APAN completely destroying my barel due to the fact that it detonates. I can machine a barell that would withstand any where from 500,000psi to 1,000,000psi...anything I want. the possibilities are endless. Even though HE's detonate, they are still simply expanding gasses that can be contained resonably.I have done many tests with AP and APAn as a propellant and beleive me when I say it is possible (anything is possible given the will and materials)
4000fps isn't really my goal, its more of a steping stone. If you knew me youd know how crazy of an additude I have towards things that I do. I take everything very seriously and never fail ounce I set a goal. I firmly beleive ANYTHING is possible.
I am very aware of 50BMG sabot rounds that shoot .30 cal bullets at well over 4000fps. thats all fine and dandy but I want a bit more. As I said, 4000fps is a steping stone. After this step I will leap towards my goal of 5,000MPH which is somewhere around 10,000fps, +or- 1000fps. The X-15 made by NASA reach a speed of 4,628MPH so why couldnt a little bullet? Im using either tungsten carbide or stainless steel for my main projectiles and either brass or AL fo a sabot. Railguns use tungsten projectiles inside an AL sabot. The world record set by a huge railgun is far past my goal so it IS possible with commercial materials. I hope to get 10 shots with my weapon before it destroys itself.
Although nitrocellulose is fast enough I dont like it. Ive used it before and found that without perfect conditions, only rifle speed velocities can be acheived. Rifle bullets cannot freely travel down the barrel and neither will mine but I dont know how much pressure I should make it require to travel down the bore. Any suggestions? Tomarow Id like to make a trip to the metal store cause it's my fathers day off. Wish me luck. Thx

[xyz]

I thought railguns had to use a magnetic projectile to work? Tungsten and aluminum aren't magnetic...

Anyway, the reason you can't use anything that detonates is because at those kinds of pressures and temperaures, the steel will simply bulge or crack no matter how thick it is.
It won't necessarily bulge the outside of the steel either, it will make the ID of the cannon a bit wider each time until it breaks.

As a sidenote, I have recently made a very small BP cannon from stainless steel. It is 30mm OD with a 13mm bore diameter (perfect fit for half inch ball bearings or fishing sinkers), and it is about 20cm long.

[Blackhawk]

No, coilguns need a magnetc projectile, railguns work on a different principal involoving induced fields in the round or something like that (I am unsure) But the powerlabs projectile was made of Al and I have heard that you can also use graphite.

[keith]

Im not disaggreeing with you because I know how knoledgable you all are and I'm envyous of it but I have to disagree.
The steel I use isnt even scratchable! when a barrel with one inch thick walls is made out of this steel......I cant imagin it being damaged. The time the Explosive is detonating and decomposing isnt long enough to melt anything or make the steel loose its heat treating. like a gun barrel stays pretty cool after only one shot. SWAT has a bomb containment crue that uses a big globe type thing made from kevlar and stainless steel. It is only about 4'x4' and the walls are less than 2 inches thick even with the kevlar. They said it can withstand 25 pounds of c-4!!! thats near to 20 pounds of RDX!!!!!!! come on now

no, railguns do not need magnets. yes, they cah use graphite(dont know why though)

Nice cannon xyz. Im getting sick of spending $$$ on materials to build huge heavy one use cannons. My next cannon will be smaller like yours. Still powerful though huh!!! shoot a ball bearing through a damn cement wall

[Blackhawk]

Yes but you can be guaranteed that the bomb tub swat has would only NOT FRAGMENT with 25lb of C4, that isn't to say that it wouldn't shatter, it is most likely just the kevlar holding the bits together at that point (very high tensile strength per fibre) The same thing was done with the lugage compartments in comerical airliners, if a bomb goes off in the hold the metal container ruptures but thick kevlar netting holds the container together and vents the combustion gasses slowly after they have expanded inside the box. High explosives are quite powerful enough to total most things, that is not to say that your cannon may not work, there is no harm in trying as long as anything is WELL away from fragments, and if it works first time it is likely to blow on a second or third shot, so be wary.

If you want to learn about railguns go to the powerlabs site, they explain the theory behind it.

[keith]

Yes I wil be very careful. I got my steel for my main barrel today and Phoenix Metal Supermarkets for only $22.00!(I'm friends with them. I will turn it in the lathe tomarow at school and make my bore. The diameter will be 3/8" then polished out to an even .50. The proccess should take a few hours for the first drill then I'll leave it for about 7 hours while it's polishing the bore.
The bore will be drilled only 20" down the Steel bar(oh by the way my entire cannon is made from one solid bar of stainless steel) the entire peice is 24" long so that leaves 4" in the back of the cannon in which the fuse hole will be drilled. I didnt want a hole in then walls of the cannon so the hole will be drilled through the rear 4 inches of steel.
My first charge will be 1g of AP along with 2g of smokeless powder (NC+other shit) I will CAREFULLY pack the charge in the back so when the AP detonates the wave front doesnt SLAM the walls but simply pushes on them. I have alot of expirience with AP so please dont warn me about it. My projectile will be a .45 cal steel ball bearing for my first "light" shot. I will use a cotton sabot to ensure the Bearing is secure in the bore. I know a bearing isnt the most aerodynamic projectile I could use but until I turn some bullets with the lathe it will have to do.

Yes I've seen powerlabs railgun. It is a very impressive website made by an even more imprssive young man.

Oh yea the wall thickness of the cannon will be 1" as I said before......man it's heavy and beautiful!

[xyz]

Two things...

1. If your propellant is one that detonates then don't stand too close to the cannon no matter how strong it is.

2. You say that you can't scratch the steel that you are using, that means it is very hard. Very hard steel is avoided where possible in modern firearms, due to the fact that it can eventually shatter due to it's hardness. The shattering problem will be greatly increased if you use a HE as a propellant, as shockwaves love to shatter things. If I was going to make a HE powered cannon, I would use a softer steel that I knew would bulge instead of shatter if it were to fail.

Just stand well back.

[Flake2m]

The other problem with cannon is that you have to make sure that the breech is fairly secure because if the charge is too powerful or the projectile gets jammed the beech will blow and the cannon will misfire.
I would stick to BP, perchlorate or BC compositions, because they have been proven to work and are generally more stable and reliable.

Also since my length of pipe is open ended, what would be the best way to make a secure breech without needing complex equipment?
The only idea I currently have is to drill several holes about 3cm from one end and then use them to secure a large block of cement/wood with bolts.

[keith]

There is no breach.... read my last posts.
The steel is damn near un-scratchable but feels softer then cold rold (go-figure)
I started machining it today and it was painstakingly slow. I'll need another day to finish.
Flak2m, I cant use black powder or anything because I want muzzle velocities around 10,000fps
And as bad luck would have it, the only energetic materials I can think of with high enough velocities all detonate.
When unconfined and in low quantity, AP deflagurates alot like NC. The expanding gasses will gently put pressure on the walls of the cannon like NC does just before it(the AP) detonates.
You say dont use propellants that detonate yet at the same time you praise NC for being a great propellant..............it detonates. Nitroglycerin is in smokeless powder............it detonates

[apathyboy]

Nitrocellulose does not detonate when used as a propellant, it burns. It needs a blasting cap to get it to detonate, and if it was to detonate in the chamber of a gun, it would blow the barrel apart, and maybe shear the lugs on the bolt and send it through your head.

Frankly, there's a reason the military doesnt use any HE's as propellants (it's not like cost is a problem with the US military): they don't work. You need something that will give a steady high pressure from gas being generated, not a millisecond long pulse of a couple hundred thousand PSI from a detonation. If you're set on using high explosives to propel something, build a claymore or an EFP.

In fact, larger caliber weapons use a specially made coarse powder to allow it to burn for a longer period of time, and if long burn times are needed, HE's are not what you want.

[xyz]

Yeah, the nitrocellulose and nitroglycerine used in smokeless powder don't detonate, they both just burn rapidly. Try reloading a bullet with AP instead of smokeless powder and seeing what happens to the gun (stand far away behind solid cover, pull the trigger with a string).

Smokeless powder can create 80,000 PSI, stuff that detonates can create several million PSI along with a very high temperature and a shockwave.

[AsylumSeaker]

Has anyone tried creating self proppeled projectiles for there cannons? It would not be too difficult to manufacture them, provided you had access to some machinery.

[xyz]

Self propelled projectiles? Do you mean rocket type things or a projectile with a powder casing?

And Flake2m, it is much better to make cannons from a single piece of steel bar stock. However, there are ways of safely blocking one end.

The way that comes to mind is taking a piece of steel bar that is a perfect fit in your cannon, then cutting off a piece several times as long as the width of the bore. Then you drill lots of holes in the sides of the cannon at the breech end. You then slide in the piece of steel bar until it covers all the holes from the inside, and then weld into the holes to fill them up with steel.

Or there is the old kewlish method of crushing one end closed in a vice and then folding it over...

[kvitekrist]

I guess a bigger powder chamber would work?

Just drill a bigger hole from the back end and make a heavy breach plugg.

[xyz]

If you are going for high power, then you want your cannon to be made from a single piece of steel and not have a breech plug.

Instead of using a larger powder chamber, you just have to fill a longer length of the bore with powder. This is fine with cannons but can't be used in rifles because excessively long cartidges are difficult to make actions for, one of the reasons that the military now uses .308 instead of .30-06

Over a certain amount however, you will be adding large amounts of extra powder and seeing little extra effect on projectile velocity. This problem persists in any firearm, not just cannons, and it is why there are only a tiny handful of rifle cartrdges that are capapble of exceeding 5000fps. Still, I have always wondered what would happen if someone necked a .50BMG down to .17 :D .

[Ammonal]

XYZ: Do you remember Elmer Fudd and his shotgun (cartoon) bugs bunny puts his finger in the end of the barrel, Elmer fires and BOOM his shotgun explodes and Elmer ends up with a blasted, black face.
Nice suggestion though, might shorten up the ranks of kewls that have been about and posting lately if they try it ;)

[xyz]

It was mostly just a joke, but I still wonder what velocities you would get if you ever did do that and had a weapon strong enough to fire it. The barrel would burn out after 10 or so shots though.

[udtst]

a really good mortar/plans can be seen here: http://www.angelfire.com/ar3/udtst/mortar.txt

Me and a friend built one for fun and it did pretty good. The projectile ranged about 400-700 yards, and caused a fairly large blast radius.
The hardest part about it really was makeing the fireing pin. It has to be dead center or the projectile will not fire.

12-gauge propellant cartridges can be prepared ahead of time. Remove the shot and shot-cup from the cartridge and then push a thumb-tip-sized piece of cotton as wadding over the powder and secure it in place with a bit of glue.
Propellant should be 30 to 60 grains of Bullseye or Herco shotgun powder or a shotshell full of Hodgins' Pyrodex CTG. Exact loading will depend on the weight of the projectile, the distance the shooter wishes to fire and the quality of the tubing used for the mortar tube.

[Rhadon]

udtst, please change the extension from "mortar.txt" to "mortar.htm". Else we have to read HTML code. Usually one should try out things like that before posting them.

[udtst]

weird, I can't get the edit link to work. anyway the link is now http://www.angelfire.com/ar3/udtst/mortar.html

Sorry about the mess-up.
Also, you all have probabaly seen it before. I just saw the same type of weapon in "nbk2000 pdf" though I have a diagram of the mortar that it didn't. I did not get it from there though I found it in a guerilla warfare manual. I'll load the manual to web and post it later for you all (as well as some other manuals.)

[AsylumSeaker]

Sounds good udtst.
I have a bunch of drawings of what I meant by self proppeled projectiles and I got it up on my page: http://destroy.100megsfree5.com

[udtst]

Ok I see what your after now, an rpg. In the "Rocket proppelant for horizontal launch" topic I said some things about funneling the gasses to produce more thrust. of course that will depend on what type of metal you use becasue each one has diffrent pressure limits. anyway tell me how it does.
By looking at your pics it should do good good :)

[FragmentedSanity]

udtst - Or anyone else interested - for a more complete writeup of your mortar search out, and download the NBK200.pdf file.
The pic's you used and some more are there along with written instructions. NBK sayas in the PDF that the article was OCR'd from "Ragnars Big Book of Homemade Weapons" so thats prolly another place you could look. Your cutaway pics make a nice addition tho.

NBK's pdf is something everyone here should have - download it from here (http://gibbonet.hostrocket.com/Nbk2000.pdf) or just look under his signature.


Ak.... I didnt see your second post about it... Which manual are you refering too - I thought I seen most of them but I cant remember another off hand with that... hmm I have vague memories of something else now that I think about it.
Anyway I wasnt trying to diss you or anything - just point you to more info - even if it was redundant :)

[udtst]

The file I got it from was one called WMR(White Resistance Manual). Just to let it be known I am not a racist. I just liked some of the info in it and wanted to learn more. I'm posting alot of the files I have to the FTP and might/will make links on a web page to get info on weapons, device's explosives and more.

FragmentedSanity
it's cool. if you can add to or see any mistakes I make feel free to correct them(this goes for everyone). Our toys won't get beeter unless we modify and correct them :)

[AsylumSeaker]

Would concrete effectivly plug the end of a pipe so it could be used as a cannon? Or does it need to be stronger than that?

[udtst]

yes, it will work but after many shots it will be more likely to crack.

[FragmentedSanity]

Are you talking about concrete and an endcap that screws on - effectively using the concrete as the lead is used int the Pics udtst posted? or just plugging up one end with concrete? The former might work - but lead would be easier to deal with IMO, and the concrete would weaken with each shot - the latter might work once or twice but Id think it likley that the charge would just throw the concrete back out like a projectile - I spose you could fill it up fairly deeply - like a 6inches to a foot of concrete in the bottom of the pipe - but I still wouldnt trust it - better to get a good endcap - or even better to mill it out of a single piece of steel.
Concrete might work if you used a relatively slow burning propellant - to lob you projectile with a low pressure, but I think it generally a bad idea - best to build someting properly if at all - cannons arent toys ;)

@udtst - I thought it may have been that one. The WRM is a pretty decent manual all told - regardless of the politics, quite similar in many ways to NBK's file - well worth a read, as you said - you dont have to agree with the views, there is valuable information to be had - as is the case with many of Aqualiefer's files - incase anyone hasnt seen his download page yet its here (http://www.varkoume.com/shared/index.php?usr=Aquilifer88)

[udtst]

I went to that page signed up and everything but I can't download anything. what do I have to do to get some of those? a special program or something?

[Jacks Complete]

Ok, all those people who want to use an exploding charge, of whatever HE they choose, please stand well the fuck away from me!

If you are immensely dumb, go ahead and prove that high explosive will cut steel, destroy concrete, rock, etc. no matter how thick. The blasting and mining industry already know.

For anyone undecided, consider a handgrenade, filled with just 4oz. of explosive, surrounded by about 4oz. of cast iron, or, in more modern designs, high tensile steel that just happens to form razor sharp bits when BLOWN TO BITS by HE.

Further, consider the modern rifle which fires smokeless powder-powered cartridges. Normally, it isn't a problem. Increase the load far enough, and you start to show signs of pressure, but in a modern target rifle, you will need to hammer the bolt open before you get the action to fail. Reduce the load far enough, though, and you get flashover, which means that your powder charge burns all at once, effectively detonating itself. This has, on more than one occassion, blown these same rifles to bits, using less than a tenth of the load that wouldn't damage the rifle even though it were 10% over maximum.

The brissance is the key. That shockwave cuts steel, by simply exceeding the yield strength of the steel (or anything) by orders of magnitude, blowing it to bits. Small charges that are allowed to expand and cool/slow slightly mean that thick steel will yield rather than fail, but repeated shockwaves will still make the steel, no matter how thick, fail. How do you think craters are formed?

Exceeding the tensile yield strength means the steel never returns to the original size. Below the yield strength, it bounces back, and so can be used again. You see this every day in plastic carrier bags. Too much load and they stretch and never recover. Beyond a certain stretch, they become useless, as they suddenly and rapidly fail. The danger is, they fail even if you reduce the loading! They have already lost all their strength.

The bomb disposal shields are mostly to stop the blast fragments, by the way. They are also spaced off by a fair way, massively increasing the time over which the force of the explosion has an effect. This stops the cutting action, and simply becomes a large pushing force.

[AsylumSeaker]

I wasn't talking about the pics udst posted. Iwas talking about filling the end of the pipe with maybe 1 foot of concrete. The conrete being smashed by the proppelant is what worried me. Perhaps cement can be mixed with something else to make it work better? Or perhaps if the problem is that rather than the cement being smashed apart, it gets fired out in a solid lump then you can screw an end cap onto the end keeping the conrete in?
Also- in the nbk2000.pdf the mortar section includes a description by the author of how they tested the mortar. The projectiles were fired into a field. The cases didn't rupture or anything and worked fine. What about a concrete or other hard surface? Somehow I don't think the projectile would withstand that kind of impact.

[FragmentedSanity]

udtst : The links are for the edonkey P2P network, I prefer Overnet - so just download either program and then click the links - Some of the files can take a while but they get there eventually. Check around the site there should be some links - and more info.

[udtst]

FragmentedSanity
Thanks, I got Overnet and it's working now. a little slower then kazaa which I am used to but good. Some of the files that I been looking at on Overnet were NEVER found on kazaa though :)

AsylumSeaker
If you want to keep the concrete in there your going to have to reinforce it some how. An Idea off the top of me head is to put rods through the pipe. example:

=======================
| | |
| | |
=======================

= pipe
| rod
step 1
Drill a hole in the pipe and place rod/rebarb(think thats how you spell it) trough. cut off with a little overhang on both sides.

step 2
Get a arc/mig welder. if you don't have a welder try using JB cool weld ,which you can by at walmart. weld the overhang of the rod to the pipe itself. this way you don't have a concrete and metal "lump" being fired out.

Step 3
If you used the jb weld pray it holds

[AsylumSeaker]

It probably sounds a bit kewlish, but wouldn't it be actually stronger to just bend the rods over on the outside of the pipe than to actually weld them? Won't look as good, but its easier.

[Blackhawk]

I suppose that would depend on the quality of the welds, if you do a good job they will be as strong as the metal itself and it should be stronger. However if you did bend the rods they could be pulled back through the holes/elongate the holes as the cannon if fired, making it more likely to blow. Also the concrete may not seal the holes properly and you would get massive power loses.

[Ammonal]

If you are not going to weld the rod in place how about using some 'brooker' rod (threaded rod), drill your holes through the pipe, place the rod through; cut to length and put a nut on each end of the rod. Bending the rod over would be very ineffective, but may work for a couple of shots.
About the concrete dont use the regular mix for 25 MPa, Add extra cement (like double the normal amount), the concrete will dry quicker and if you can leave it a week to harden it will withstand alot more impulse and pressure. This higher cement/sand/gravel mix gives a higher MPa rating for the concrete, they use it for anything that will have a high load ie > 5 metric tonnes in runways, highways, bunkers, etc.
Hope this makes the person who suggested using concrete live abit longer by not having poor workmanship on a device that DOES require some decent standards. Not just 'bending the rod'

[Lurking_Shadows]

I've been working on a PVC hand held mortar thing, so far the first test was a flop the trigger system messed up on me and I need more fuse.

Until I get more tests are on hold for me.

I'm also trying to use AP as a primary lifting charge why I don't know but the projectile is well wadded to absorb the impact.(hopefully)

http://www.geocities.com/taipan526/Mortar-Gun.html

[SMAG 12B/E5]

I have enjoyed this thread, but would like to interject several observations. Stop trying to use a Class A explosive as a propellant or get good insurance. Weapons designers arn't ignorant of the forces necessary to launch a projectile safely. A weapon should be more dangerous to the enemy standing in front of a weapon than its operator.
Concrete is a poor material to be used as closure for a barrel of any sorts. It might serve as a remotely-fired one-shot ambush device. Consider a machine-threaded alloy cap or a welded closure with sufficient post welding heat treatment. Cast iron pipe caps have poor strength.
The homemade mortar mentioned is similiar to the one I fabricated while in high School (am 57 yrs old). Mine was barreled with 2 inch black pipe and fired a projectile fabricated from 1.5 or 1.25 fittings. The rear of the projectile was of 3/8 inch pipe closed with a brazed plug, cross-drilled (12 holes .25), primed with a shortened 45 cal long colt cartridge. The cartridge was primed with 2 toy pistol caps and BP. This ignited the propelling charge (contents of one 30.06 rifle cartridge) contained in a tissure paper and wrapped around the tail of the round. Almost killed our milk cow on my first shot (100+ yards, elevation approx 80 degrees).
Those interested in extreme mv might want to research Hitler's long range artillery project that was destroyed by Allied bombers before it could be used. Another method might be by the use of saboted light weight projectiles with reasonable propellant charges.
The self-propelled projectile will work, but not efficently. You might consider opening the breech of your barrel, changing your powder configuration ( for complete in-barrel burn ) and produce a workable recoiless weapon. The combustion of all propellant while in the barrel will allow user to hold and sight weapon (only after thourough remote testing). It will still sound like a cannon but will be more managable. Apologies for length of reply...

[keith]

I'm very sorry for my absence these last couple weeks. My idiot neighbor was using my computer without my knowing and crashed it. As you can see, it's fixed now.
I finished my cannon and have tested it many times now. It's been fired 11 times now without rupturing or cracking. My charges are composed of 2g of AP,5g AANo.7,1gNc. Apon test firing my cronograph failed to give me a reading. I figured my battery was near dead so I replaced it. Apon second testing still no reading, same for the third fourth and fifth. I stoped testing because its pointless without a cronograph. I was reading my manuel for the crono and noticed its maximum velocity reading is 5500fps. My crono is either broken or I've passed it's limit. I fired it 6 more times then checked for stres cracks or buldges, there were none. The cannon is unharmed.

[keith]

On Cival-War-type(conventional) cannons, how much do you think the fuse hole takes away from the strength of the barrel.
I bought a new barrel for my next cannon (its DOM seamless high carbon 4130 steel, 1/2inch walls thickness, I.D.=1.5, O.D.=2.5) The fuse hole can either be drilled through the barrel wall or through the breach plug with is many inches thicker than the barrel walls. The PSI limit of my barrel is around 65,000psi so it's no weak lil pipe. I'm going to be using excessively powerful charges in this cannon so Im worried that if the fuse hole is drilled in the barell wall, it will rupsure. Any thoughts on this???

[Anthony]

Lurking_Shadows, AP propellent in a PVC (handheld!) mortar - you are going to die!

Everybody using closed breach canon, what are you going to do if you get a missfire? I.e. how are you going to empty the canon to reload?

[Blackhawk]

With the quality of construction of the closed breach cannons proposed it would probably be easier (and safer) to chuck it out, just stick a large HE charge or SC to the side of the barrel over the powder and detonate so you can insure the powder has been destroyed and the cannon will no longer go off.

[keith]

Sorry about the double post, after posting once, it failed to show up on the web page so I figured something went wrong and it didn't post for whatever reason and I reposted something else I wanted to mention.

I always use breaches on my cannons unless I'm worried about the pressures being too high.
I don't really like "what-if" questions. IF a cannon failed to go off, there are projectile removal rods you can buy or make for under $20. What would make a cannon not go off when lit by a fuse? Missfires arent a problem in the world of cannons and mortars. The odds are that it will go off and if by some freak chance it doesn't, you can remove the powder and projectile without strapping a brick of RDX to your $$$$$ cannon. Real cival war replica cannons cost anywhere from $5,000 to $45,000 and do not have breaches......
Why do old cannons have such thick walls. Most cannons youll see have atleast 2 inch thick walls and are made from brass, steel, iron, or copper. The powder charges used arent much more than what I use in my small cannon that has only 1/4" walls.
Does anyone know who came up with the idea to use such thick walls? think of how many cannons one cival war cannon could make if it were melted down and re-molded into thinner walled cannons. Doesnt seem very cost effective during wartime does it?

[xyz]

Anthony, that was a problem that troubled me for several days until I finally thought of a good solution.

Whenever my closed breech cannon has a misfire, I take a glue stick (you know, the ones used for hot glue guns), attach a stick to the back of it so it will reach down the barrel, and then heat the end of the glue stick for a few seconds with a lighter. I then quickly push it down the barrel and hold it for a few seconds while the glue solidifies again. Then I pull it out with the projectile attached and then pour the powder out of the cannon.

After use, you can simply take a knife and cut the end off the glue stick and use it again. Any glue that get stuck to the bore of the cannon (which won't happen if you are quick/careful enough) can be removed with a piece of stiff wire (the glue comes off easily because it doesn't adhere very well to smooth metal).

Obviously, at 13mm bore diameter my cannon is very small, but this idea could be adapted for larger cannons

[keith]

The projectile removers that were used during the hay-days of cannon use were very similar to easy-outs. Those things used to remove a stripped bolt or screw. The tips were very sharp and easily dug into the lead balls they used (I use steel :()
The tip of the long rod would screw into the lead ball with little effort from its operator then youd simply pull it out.

XYZ, if you can remove your projectiles with hot-glue then they are not very tightly in you barrel right? 13mm....thats about a half inch. Glue sticks are a half inch....... If your cannon is 13mm it is the same size as many blackpowder muzzle loaders. A good idea might be to shoot muzzle loading projectiles out of it which would not only give you improved performance but would enable you to use a romoval rod.

I use FFFFG in my mortars and FFG in my heavy walled cannons. I use simple cannon fuse ignition. What about you all?

[Anthony]

I suspected something like an easy-out, but what if you're not using lead or other soft projectiles?

Keith, I think the difference between wall thickness is that ye olde canon were cast, and yours is made from drawn, high strength alloy steel!

[keith]

Yes that seems the only explenation that makes sence but is cast iron really that week? On Mythbusters(TV show in teh US) they made a black powder cannon from a tree trunk. it shot a 3" diameter ball of cement out of sight using 6oz!!!!!!!!! of black powder. The wall thickness of the tree cannon was only like 4 inches. So I guess a tree trunk is as strong as cast iron.

I use steel cylinders or ball bearings for my projectiles so I cannot use th easy-out rod method but since I always use breaches on my cannons misfires have never worried me(plus Ive never had one and cannot understand how one would have one)

Does anyone know where one might aquire a Feild Howitzer barrel from the Marines? The barrels must get damaged every once and a while and I doubt the Marines have an Acme howitzer melt down and remold plant at the base so they must send it away to be melted down and the steel recycled. Maybe one could just buy the howitzer barrel from facility before they melted it. Theres only about 300 dollars wourth of steel that makes up the barrel so 600 bux waved infront of the steel plants owners face might intrigue him.


Oh yea, any word from that Lurking_Shadows guy that planned to use AP as a lift charge in his PVC HANDHELD cannon? I hope hes alive.....

[NickSG]

The treecannons walls were more like 8-12 inches thick, and they had steel reinforments.

One of the reasons why the walls of the older cannons were so thick was to add weight. The smaller cannons would have so much recoil it would take much too long to reaim. With the heavier walled cannons, the cannons didnt move as much resulting in quicker follow up shots, along with allowing the cannons to be set up on ships.

BTW I use Visco to light my cannons, although I occasionally use Ematch.

[keith]

Why didnt they use thiner walls to save material and have 100 cannons on the front lines instead of 30? As for the recoil, just equip each cannon with a muzzle break. As for rate of fire, with 3 times as many light cannons on the line you'd get alot more shots than with 1/3 as many heavy cannons. Can you imagin 100 cannons shooting grapeshot at your front lines from 200 yards???? 100 cannons plus 25 grapes(balls of lead) per shot @ aboput 3 shots per min 200 meters away........it would take about 2 min for a group of soldiers to run cloeenough to the cannons to get off some shots at them and finaly take out one or two cannon operators. By then the cannons would have sent.....25x100x3x2=15,000 half inch lead balls hurlled down range in 2 min. Seems alot more hazerdous to your enemy than the normal 30 cannons used shooting big solid balls. Plus both side would have about 300 infantry soldiers there returning cover fire for the cannon operators. It woudl be a seige with fire from cannons doing all the damage. Both sides given the same resources and quantities of raw materials(lead,iron,cotton) the side with 3x as many cannons would win no?

[Ammonal]

First, I am hoping that the AP mentioned earlier was short for ammonium perchlorate not the common acetone peroxide.
Keith, a few ignorant corrections: we have known about muzzle brakes for the life of brass cartridges for breech loading weapons. As for having three times as many cannons, you would need three times as many men, huge supply lines, and a very big area to spread out your '100 cannons; raining down 15000 shots'. As for normal armies and artillery they did not occupy huge areas and they didnt unleash rains of innaccurate and basically wasted ammunition. They tried to cause as much damage and inflict as much pain as possible per round fired. I also presume you are thinking of the massive old cannons from centuries ago. There is also another thing called resources which an army must have to be able to supply 100 cannons to a particular front.

Can we stop talking about the old massive cast cannons and get this thread back on the topic of making "Home made cannons, Howitzers and mortors" not 16th century lead shot?

[xyz]

kieth, the projectiles aren't exceptionally tight, just tight enough that they won't move around in the barrel if the cannon is tilted or bumped.

[keith]

Formula - Bullet weight (grains) x velocity (feet per second) squared / 450240 (constant)

Using that formula, my new cannon (1.5"IDx2.5"ODx48") shoots a 1pound projectile at an average of 700fps. Whats the formula for converting oz to grains?

[Rhadon]

Keith,
check your mail.

[keith]

xyz, Have you ever considered using muzzle loading sabot bullets with it? They make a bunch of different calibers ranging from .45 to .85 I think. What length is the barrel?

Rhadon, I dont use my email because it doesn't work.
I'm sorry for my last post. I know senceless posts are frowned apon and it won't happen again.

Does anyone have any designs or plans for sabot projectiles? I normaly just use cloth wrapped around the bullet but I'd like to start using a solid and more reliable sabot like plastic or maybe even aluminum. Any ideas for a shotgun type wad? Depending on the bore diameter, you could use plastic soda bottles with slits going down the sides.

[NickSG]

There are about 7000 grains in a pound, and about 15 in a gram.

A design for a homemade sabot I thought up several nights ago consists of a peice of dowel and the projectile. A peice of wooden dowel (at least 1 1/2 times the length of the diameter of the barrel) is cut off. A hole is drilled all the way through the center of the dowel. The hole must be large enough to fit the projectile inside, but not large enough to where the projectile will slide through too easily. The projectile is taken out and the dowel is cut through the middle (lengthwise) so there are two separate halves. When loading, the two halfs are put together, the projectile is put in the middle, and the sabot it to be loaded through the muzzle.

Unless you can find the perfect ratio to rifle the barrel, do not make the projectile and longer than .75 times the diameter, becuase the projectile will tumble, decreasing accuracy and penitration.

[keith]

Yea I've thought of that it's a pretty good idea. I'll give it a try and post results. I wont have a chance to test my new cannon out for a couple weeks :( It's barrel diameter is 1.5 inches and my projectiles are normaly 1.25 with a cotton sabot. I think 1 inch would work betetr with the wooden sabot you talked about rather than 1.25 like I normaly use. I dont understand what you said about the projectile not being more than .75 times longer than the diameter. So your saying the projectile should be short and real wide? My projectile will be 1"x4"(like a bullet kinda) and made out of brass.
One flaw with your design though is the hole for the projectile cannot allow the projectile to slide through. You said "A hole is drilled all the way through the center of the dowel. The hole must be large enough to fit the projectile inside, but not large enough to where the projectile will slide through too easily." Well the projectile must not be able to physicaly fit through the sabot. There will be about 10,000lbs of pressure pushing the projectile forward apon ignition and about 20,000 on the sabot. Say your projectile is 1 inch in diameter at its widest point, the hole in front of the sabot may not ecxeed .75 inch. Remember also that wood can compress alot(espescialy pine)

[NickSG]

Good point. I was thinking about changing the design to where you drill to about 1/4 inch from the other side. That way, when the cannon is fired, the gases wont touch the projectile. Also, when wood is used, the projectile will compress front to back, cuasing the sabot to expand to the sides of the barrel, improving accuracy and velocity.

What I meant by no longer than .75 times the diameter is if your projectile is .5 inch diameter, dont make it any longer than .75 inch. There will be no rifling to stablize the projectile, which will cause it to tumble. A little tumbling is ok, especially in flesh, but when the projectile is too long there will be too much material resistance on the bullet, lowering velocity and penitration.

Perhaps if you can get the sabot going fast enough, a cast lead bullet will have enough energy to fragment while tumbling, much like the .223 FMJ? With a solid lead core I dont think the velocity would need to be any more than 1500 FPS, if that, and since the projectile will be tumbling anyway, you can use a solid cylinder, which will allow the projectile to weigh more.

[keith]

Any ideas on a rifled sabot?
I normaly make muzzle breaks for my cannons but on this one I'm not so That I can play around with shotgun (grapeshot) type ammo. I wanna try a wad of some sort with like 5000 BB's infront of it. Shoot it at a close target......WOW

[xyz]

kieth, a word of advice, never attempt to fire a saboted projectile through a muzzle brake unless you are sure it won't open up until well after leaving the barrel (like a tank sabot round). Otherwise the sabot can open up inside the brake and then exit through the front of the brake taking half the brake with it.

[keith]

I hadn't planned on making a muzzle break for this cannon. I always make sure nothing is in the way of my sabots or wads.
I think the cannon weight will keep its masive recoil at bay.
I will post pics as soon as I figure out how to. I dont have a camera but my friend has a real nice one. His camera isnt capable of being loaded onto my comp so I'll set up an account to the E&W forum on his comp and load them that way. Any mods mind if I do that? I'm on the second stage of many in making this cannon and I have already spent $150
IF I do decide to adapt a muzzle break on this cannon due to it tremendous recoil it will be more of a pepper pot esign than a single or double baffle as used by the military.
With a pepper pot desin, not sabot could get caught because the holes will be small. google search for pepper pot muzzle break if you atre unfamiliar with what they look like. I put the utmost care anbd effort into my cannons, it's guna be amazing.
Now if you'll excuse me I have to go do EIGHT hours of milling.Im begining work on my breach. One wrong move and I wasted 40 bucks.

[Jacks Complete]

Just for info:

Yes, cast iron is that weak. Cannons used to burst quite often in the early days. A slightly wrong mix of stuff in the crucible or furnace, and you got a big bomb. A slightly over-sized charge, you got a big bomb. A slightly off-round ball and you got a big bomb.

Not good when it is in your ship, and it has just taken out half the gunnery crew, and made a big hole in the side...

As time went by, and machining cast iron became possible, and steel got more common, and the processes became more scientific, the charge size went up a long way, as did the calibre. However, it still didn't take much to have a problem, and so caution was applied. Indeed, it still is, as we "proof" all our guns to 30% more than the standard to ensure they are safe, without some fatal defect in the steel.

An example of the size vs. wall thickness trade-off can be seen in "Mons Meg" the huge cannon in Edinburgh castle, used many years ago (1457). It split, and its twin has been lost forever. It weighs over 6 tons! http://www.rampantscotland.com/know/blknow_monsmeg.htm They stopped using it as it was still too heavy, even though it failed due to the walls being too thin!

Anyway, hope the milling went well.

[keith]

No it's not going well I broke my $35 bit. I have more obvioulsy but it'll take longer now. I could have avoided milling all together by just welding two .5"x1.5"x6" steel plates onto the square breach bars but I want it to look real good and be extremely strong. Youll see when I post teh pics...can't wait.
Yea that cannon was big but have you seen Hitlers mountian cannon? I dont know alot about it but it has like 15 different chambers full of powder along the barrel so they would ignite at different times so there isnt a pressure spike. And it's on the side of a mountian :)

BTW, when I have my pics can I just email them to a mod and have him doit? That way it will be set up as you mods see fit. Dont want me, the noobi messing it up right:)

Just some cheapy mill my dad bought me for my cannons/mortars/guns.
cost like 1500 so its cheap. works though. I broke the bit by going too fast while talking on the phone with my girlfriend. It just chipped it but now its ruined.

[Jacks Complete]

Yes, but this was 1457, not 1943!

Shame about the bit breaking. Too much chatter or what? The milled block will be so much stronger, you are right about that.

What mill have you got?

[Rhadon]

keith, I think you already guessed what my email was about. But you should get a new, working email address.

[NickSG]

This (http://www.docsmachine.com/nonPB/mortar.html) looks pretty fun. Anyone else thinking of making one? :)

I have plans for a new cannon I plan on making sometime before next summer. The cannons bore will be 20mm diameter (3/4 inch), the barrel would be about 5 feet long, and will fire mini N2O (8 gram) cartridges filled with lead. The lift charge will be 100 grams of black powder per shot, and the barrel will be rifled. I will have to use a smooth barreled pipe before actually building it, since I will have to run a few test shots using the full power loads. I will chrony the results, and by knowing how fast the projectile will be moving I can figure out how fast I need to rifle the barrel. I will have to find a pipe that can stand about 20K PPSI or else the cannon will blow up.

The cannon will be mounted on a three square foot cart with four wheels attached, and I will have weld some solid steel dowels running from the cart up to the barrel connecting the two. I will be using Christmas tree ignitors (yeah, it sounds kind of kewl, but hey, it works! ;) ) connected to about 100 feet of wire.

I will have to weigh the cannisters filled with lead before I can figure out how much energy the cannon will spit out, although I estimate it could throw the cannister as fast as 1500 + FPS.

[keith]

Sounds fun NickSG.20,000psi may not be enough. 100 grams.... thats about 2000 grains which is 20 times more than muzzleloaders use yet you have the same barrel diameter as a muzzle loader. Whats the maximum deflaguration rate of black powder? I think its about 1300fps. 1500+ might be hard to acheive.
If you had acces to a lathe, turning out improvised brass bullets would be best.

Rhadon, no I hadnt guessed what the email was about and hadn't given it much thought. I assumed off the top of my head that it had something to do with my ignorant post that was above it. I'm very sorry for that and I edited it ASAP. Again sorry.

[NickSG]

Well, im not going to use only black powder. I found that mixing in about 40 percent by weight DBSP to black powder increases the power considerably, while still being cheap enough to fire 100 grams at a time. (This isnt going to be a little .22 zip gun :) )

Im pretty sure the maximum pressure BP can give off is around 17K PPSI, although I dont know how much the smokeless powder would change that. I might just look around for a used 20mm cannon barrel, although im not sure if the rifling would be good enough to stablize the projectile. Otherwise, I might just forget about the 20K barrel and skip to a 40K.

[keith]

Why not just buy a peice of DOM tubing. Holds around 65,000psi with half inch thick walls. Get an inside diameter of 1.5" or 2". It would cost about $140 which is how much a cheap used 20mm barrel will cost.
I dissagree about teh maximum pressure black powder can give off. What if you had a sealed air tight chamber the size of a baseball that could withstand 100,000psi then you ignited 10grams of blackpowder in it? BOOM. Smokelss powder will produce much higher pressures. The SAAMI maximum pressure rating for rifle loads is 85,000psi I believe. Rifle loads will have 40-250grains of DBSP powder. Can you take some pics when you finish it?

[PHAID]

Here is a link to cannons that might be of interest to you.
http://www.wildimports.com/index.htm

[NickSG]

Originally posted by keith
I dissagree about teh maximum pressure black powder can give off. What if you had a sealed air tight chamber the size of a baseball that could withstand 100,000psi then you ignited 10grams of blackpowder in it? BOOM. Smokelss powder will produce much higher pressures. The SAAMI maximum pressure rating for rifle loads is 85,000psi I believe. Rifle loads will have 40-250grains of DBSP powder. Can you take some pics when you finish it?

This will be sort of a "budget cannon". Im not looking to spend too much on it, since I do have bills and insurance to still pay off.

If you ever get the chance, empty out a .38 special cartridge. The cartridge is long, although there is rarely any more than 3-5 grains of powder in them. Look at an older .38 special cartridge, and the case will be nearly full. Anything with NC in it will burn with much higher pressures than black powder. This is why (even with the weak metals of the day) you could fill a .38 special cartridge full of black powder, but not fill it any more than 1/8 full of DBSP. Im 99.9 percent sure the maximum pressure BP can give off is just under 20K, but if you want to further investigate im sure any reloading site will have the info. I dont have too much time right now, though, sorry.

If I buy a quality digital camera sometime before its done, then yes, I will take and post pictures. Or I might just borrow a friends camera.

[keith]

So if you did have that airtight sphere with a 100k psi limit full of black powder in it you believe it wouldnt explode? You think it would just withstand the pressure? How can there be a pressure limit on an explosive? The more you add, the more pressure you can get. And If there is a maximum pressure that black powder can acheive it is one hell of alot higher than 20k. I am well aware of DBSP being much more powerful than BP due to it's ingreidants(kinda obviouse)

The powder in .38 specials is anywhere from 3grains to 12.5grains. All smokeless powders are not alike. I would be willing to put my knowledge of reloading equipment and anything at all to do with firearms up against that of anyone here. I know you take me for a noobi because of my age or the fact that I only have like 35 posts here but just because I am new to your forum(which is far better than any other I have seen) please do not treat me like one. I hope your cannon comes out nicely.
My cannon will be done soon and I cannot wait to post the movies and pics. I'm going to buy 10,000 BBs from walmart and shoot them all at once at a big plywood target at about 40 yards!!! I have several sabot designs to test and of course my normal cylinders I shoot. It will all be on tape.


I just remembered a friend of mines dad owns a black powder rifle that blew up in his face with only 100 grains in it(6grams i believe) because the barrel got clogged with dirt/mud. The max psi limit on those barrels is somewhere around 50k.

[xyz]

NickSG, the "pressure limit", as you put it, is much higher than 20kPSI.

As the pressure and heat increases, the powder burns faster, further increasing the pressure and heat, and so it burns even faster, and so on.

Unless there is a way to releive some of the pressure (such as a bullet being pushed along a barrel) then it will continue to rise until all the powder has been consumed.

[NickSG]

Im aware that different powders burn with different pressures, since I used to reload some of my own cartridges. When I was refering to the .38 special, I was using the standard pressure rounds as an example. But still, you can use a lot more black powder without going over a pressure limit than any NC. As I said before, this is why back before NC was commonly used, they had many large cases filled completely with black powder, even when the metals they used were nowhere near as strong as the modern day steels.

BTW, I dont not think that you are at all inexperienced in this hobby just becuase you have 35 or so posts. Also, what brand of powder will a .38 special allow 12.5 grains of powder? As far as I know, the maximum for .357 magnum cartridges is around 10 grains of the good powder (I could be wrong on this though). I assume that would be a reload, and you would have to shoot it out of a .357 magnum?

Anyway, good luck on your cannon too. 10,000 BBs is a lot, so unless you dont want the BBs to take up the whole length of the barrel, you might have to use a barrel of at least two inches in diameter.

I agree though, that unless there is something to let the BPs gases expand, pressures will run higher.

[keith]

IMR4227 12.5grains going an average of 1011fps. case is about 72% full w/this charge. This is my competition load for my peice_0_shit revolver(I hate revolvers!)
Yes 10,000 BBs is alot but it will handle it. The bore diameter is 1.5" so there will be about 7" of barrel volume full of BBs. That kinda scares me....my barrel alone cost $110. If this thing blows I pissed away about 150 bux.

I have decided to use my old carrage for this new cannon. My old cannon broke so the old carrage will be wasted if I dont use it anyways. This will save me time and most of all about $60 which I may use to buy some fun ammo types.
It is in good shape and should handle the bigger barrel and heavyer recoil produced. This means the pics are closer to being posted. I'm still waiting for a mod to volunteer to post them for me. I could just email them to you and you then post them. If not I'll have to wait 2 weeks or more for my friend who has the camera to get a membership here which he will never use.

[Jacks Complete]

Why not have him email you the pictures, then you post them?

I agree with keith about the BP issue. There is a theoretical limit to the pressure, but the container would have failed long before it was ever reached, if it was full and airtight. As for the .38 special, modern reloads tend to use less of a faster powder, as it is cheaper than lots of a slower powder. 4 grains of one powder will spit a bullet out nicely, while four grains of one that looks the same might get the bullet stuck halfway down the barrel, or even (unlikely with 4 grains) blow it up.

[keith]

I use alot of slow burning powder in my .38 loads cause my barrel is very long at 8".(long for a pistol) It's a peice of shit. I dont even know what kind it is.

When ever I make something nice I care about and welding is involved I use epoxy to cover the welds and smoothen them out. I then lightly sand and smoot the epoxy before painting. Makes it look like the multible parts of steel are one whole peice, or atleast looks more professional. Just some advice.


Has anyone ever seen a real claymor get triped by a live animal? Ive seen a clymor detonated near a military dumby for a demonstration. Cannons are like long range claymors with twice the power. I'm going to make a shorter cannon with the same inside diameter and set it up out in the desert with a trip wire strung along aboput 20 feet in front of teh barrel. Fill it with teh charge and about 500 steel ball bearings. Put a steak infront of it.......wait........

.........BOOM! There are tons of coyotes, bobcats, bears, mountian lions, cooons, and skunks. Somethign would trip,it within one hour if it was left out at night.(everything in Az is nocturnal)

[PHAID]

You can't compare a cannon to a claymore, The claymore uses high explosives and a cannon uses BP.
I have fired several claymores and at closer ranges (10-20m) you will be nothing but hamburger.

[keith]

I know one uses BP and one HEs but the outcome is the same...a lot of steel balls flying through the air at hypersonic speed. A small cannon is more conveinient though for multiple uses and is just as deadly.

My new cannon is almost done. I have only to finish milling the breach bars, weld them on, grind, sand, brush, polish, and paint. 4 more hours. I'll finish this weekend.

[Jacks Complete]

keith,

er... shouldn't your welds be filled with weld (steel), and then filed/ground back, rather than touched up with epoxy (noddy plastic)??

[keith]

The welds are very strong. I weld with high heat, grind down flush with surface, and reweld. After that there is a perfect bead of weld along the surface. Instead of leaving it like that I smoothen everything out with epoxy and sand it when it dries. This is for looks only, it surves no structural purpose at all. What do you mean filled with steel?

[xyz]

I think he is talking about where you build up the weld higher than the surface, then grind it back until it is flush with the surface and it all looks like a single piece of metal instead of two pieces that have been joined.

[keith]

I hate milling!
It's ready to fire.
I'm not done though. I'm going to do some more work on it to make it look better and be alightly stronger. The totaly weight is 104lbs. Another full day of work and it will be finished. Ill have pics soon.
Ill give it's dimentions again: barrel is DOM seamless 2.5 inch outside diameter, 1.5 inch inside diameter, 48 inches long. Carrage is 19 inches long, 14 inches high, and 14 inches wide. Carrage is made from 2"x1.25" heavy walled rectangular structeral tubing. Tomarow it gets grainded, sanded and painted.
Sunday it will be tested.

[keith]

I had to double post cause my last post was more than 14400 min old or what ever. I got this idea from another thread that was closed because the idea for the weapon was stupid and not well discribed.
For faster firing rates, you could take your projectiles(mine are 1.5"x4" Al or steel cylinders) and put some sort of NC based putty on the back of it either just stuck behind the projectile or inlayed into a dimple in the bullets rear. The putty would have to be strong and not fall off the projectile during storage.
There isnt much need for high fire rates when you and I are out shooting our toys but this isnt a bad idea for those of you that use NC. Instead of fuses which take up time you could use one of the things from a party popper(the thing that has a string coming out of the back of it and when you pull it, it shoots confetti).Just jam the lil thing connected to the string down into your enlarged fuse hole, pullBOOOM, and reload. Fireing would take about 8 seconds per shot and would make your cannon look more saphyticated infront of your spectators.

I have everything sanded and ready to paint, and I just bought the paint. It will be done in a couple hours and I'm shooting it tomarow with 40grams of pyrodex per shot.

[bigshoe]

as we have seen in WW1 & WW2 the most effective artillary is that that is permenatally postioned. i would suggest using a 30-40mm metal tubing about 1m long (like normal mortars) and welding two bracing arms 2/3 of the way up the barrel, and having the end of the barrel into the ground with a footing of rocks and concrete that would be dug-in onder the ground and a metal plate (to just cover the end). this would give a reliable weapon (because it holds less moving parts) and the accuracy would be very low (but its not like we are out to kill ppl). the only other problem would be cleaning the weapon out.
a small hole would need to be drilled into the base and metal tubing welded in (for detonation)
and then loaded with explosive divice and the armament.
give it a go it should work!
also a concelled OP would be need for the weapon as it is fairly inmovable

---------------------

Sixty-four thousand dollar question: Do you know what this useless key above the CTRL key is for?

Rhadon

[Dave the Rave]

Mercyless stolen from Mp5guy´s last post, at 40mm topic:

http://www.hunt101.com/img/100277.jpg

From what I understod, it´s some kind of truck part, like an suspension part, with an bore of 40mm, and as he sugested, it can hold a helluva of pressure buildup.

The idea is, with some minor modification it can be turned on an improvised Carl Gustaf Recoiless rifle like this:

http://www.urban-armory.com/images/82mm.jpg

And can shoot, as you can see, a shaped charge that looks like a RPG7 round.

I think that, if we take of that spring and add, internaly, another steel tube with the same diameter, welded at it´s back, the beastie can held an self-proppeled recoiless warhead.

Another design can be seen here:

http://www.inert-ord.net/atrkts/57mm/rifle2.jpg

The diference over those two weapons, as far as I know it´s that the Carl´s is more like an rocket launcher, and the 57mm is realy an recoiless cannon, where the proppelent is held inside of an breakable package and an perfurated shell to alow expansion fo the gases and proper counter recoill to the gun.

Both systems can be replicated with an fairly suplied workshop.

The self-proppeled round can be made with a steel tube to house the lifting charge, that can be made of gross sized BP, like the panzerfaust, and an coper plate homemade warhead.

The 57mm can have it´s shell made out of an plumbing copper tube, perfurated with an dremmell and with some PVC tubing to hold the proppelent. And both the ideas can use an non elletric cap to be set of.

What are your comments ? I think that it can be easily done, but do you have any idea ?

[Blackhawk]

Actually in his post he said it was the barrel of a 40mm 'pom pom' gun, ie 40mm exploding flak AA barrel. I knew I saw it somehwere, when I was in London I had great fun sitting in and wheeling the AA cannons around on a Battleship/museum on the Thames, although they made it impossible to lower the guns more than ~45 degrees so you couldn't scare the people in buildings :(. I didn't think a truck part would have such a nicely flared muzzle end.

[MP5Guy]

Fully Rifled 40mm AA Pom Pom Barrel. No Truck Suspension Part. Dave do you really think I would post a Pic of a Truck Part??? ;) Note Recoil Spring Still Attached.
MP

[Dave the Rave]

Nay... You´re rigth, you´ve said that it was an gun barrel but, due to my lack of english, I understood that it was some automotive part. It really looks like an suspension of a kind of truck fabricated in Brazil, the "Gurgel". It haves an internal gas piston and also haves an spring, just like the recoil spring at your barrel.

Sorry if I ofended you, I was not saying (sp ?) that you´ve posted an truck part pretending that was an gun part, but rather that you´ve posted some truck part to make an gun part...

[Efraim_barkbit]

I have some time over in a "workshop technics" class, and I´m thinking of makeing a simple cannon.
It wont be something big, I´ll make it as long as the drill bit permits, and drill from both ends, probably 40-50cm, and probably 15mm ID, and 30mm OD.
That would give me 7,5mm walls, that should be enough.
I´ll thread it 5-6cm in one end, and make a threaded endplug.

If you have any opinions about it, lets hear them.

It´s probably be done on the lesson next tuesday, and I might have some time in two weeks If I don´t finish. I have a three hour lesson, so I have enough time, if not my teacher figures out something else I must do.

[Narkar]

Do you REALLY expect to drill accurate enough for the 2 holes to meet exaclty? I dont think so. What you need is a deep drilling machine, and i dont think you would get access to that one too easy.


Better find some pipe

[Efraim_barkbit]

Ever heard of a lathe?

By the way, I just realised that the 15mm drill isn´t that long, so the cannon will be shorter if I dont scale up the bore a bit... anyway, I´ll make it as long as the drill permits.

[Jacks Complete]

Sounds like a plan!

Oh, the joys of school - free access to all sorts of goodies and equipment, plus knowledge, if you knew the right questions to ask.

Are you going to cut a square section thread? You might want the extra strength.

Hope you get it all sorted!

[Efraim_barkbit]

A sqare section thread?
I´m sorry, but I have no Idea about what you mean. Explanation please.

I plan on just threading about 5cm in one end of the "pipe", and then make a threaded "plug" for it.

[Efraim_barkbit]

There´s not going to be any cannon, I´m just home from a disappointing class… :(
My teacher didn´t like the plan, or more correct, he didn´t like me making it in school, because if anything happened and someone got hurt, it wouldn´look very good if the school had allowed a pupil to make a cannon and blah blah blah...
and to be honest, I can understand him, but that doesn´t make me less disappointed.
Why can´t things go as planned? Then I would have a lovely little 18mm cannon by my side right now

I must admit I hadn´t had a thought about the possibility that it might be stopped by him, more likely that he had something else for me that I must do.

So now I´m back in the neverending search for a good piece of pipe.

[knoddas]

Here is a picture of my cannon.
Only 12.8 mm in diameter, but oh so powerful!
38 SPL in barrel (http://img40.photobucket.com/albums/v124/knoddas/38SPLin505Gibbs.jpg)
Just kiddin', here (http://img40.photobucket.com/albums/v124/knoddas/KynochAmmo.jpg) is the real ammo for it.

+++++++++++++++

That's not a cannon, but a large caliber rifle, and professionally manufactured to boot. :rolleyes:

Know the difference.

NBK

[akinrog]

Sorry for bringing up an old topic.

Do you watch mythbusters on Discovery channel. The guys are very entertaining and quite informative :)

Sorry again if this post seems kewl as you refer to it.
Anyway today I watched an episode involving a Hungarian myth which is related to a tree cannon (a cannon whose barrel is made of a hollowed out tree log).

According to that myth the Hungarian villagers constructed a tree cannon overnight and used it. But they used too much gun powder and it exploded.

They actually tried it. First they constructed the tree cannon. They first took a large diameter log and attached three iron belts at the breech and three iron belts muzzle section of the cannon using old fashioned methods. Then they drilled the bore of the barrel (first by old tools that Hungarian villagers are claimed to use, but since they failed they used a power drill).

One of the guys carved a cannon ball out of a granite block by using chisel and hammer.

They hired a licensed explosive expert and tested their cannon with a gunpowder charge and it standed.

After the successful test, they took their tree cannon to the field and tested it first with a tennis ball and then the granit cannon ball.

The tennis ball flew a length of footbal pitch. The granite cannon ball flew so away that they could not find it. Finally they used two pounds of powder and plugged the muzzle with an aluminum plug and made it explode and shatter apart.

I mean it is very interesting to convert a (large diameter) tree log which is secured by means of iron hoops into a cannon. Regards.

[deathpickle88]

i saw that show, it was great.

Ive made quite a few pneumatic cannons. One had a 1" ball valve and it shot marbles. lol
I have found making the air chamber about 1:3 ratio larger than the barrel, it produces better results. This is because there is alot more air being forced through the ball valve. so naturally their is a lower psi pressure rating and it is alot safer. always use pressure rated pipe.

[THAT Dude]

I think that if you are making a home made mortar you are allready putting what amouts to a zip gun barrel on the back end of your shells.
So it should simplify the mortar to attach a firing pin to the shells zip gun style.
That way you do not need to center a firing pin in the mortar (eliminating the "hard part" of bilding a mortar).

[FUTI]

to akinrog: I didn't watch that episode of Mythbusters but it is very common and true story...in this part of the world the rebels against the conqueror(or ruler) often used this "wooden canon technology" in order to have at least some kind of artillery for a combat. It does work but the range of projectile is shorter due to lower charge that can be used safely, and you must use projectile that do not damage barrel (soft material is better). As I remember it is cherry tree trunk that is used since it is "soft wood" that can be easilly bored to make a nice barrel . And also little material elasticity on charge detonation doesn't hurt I think and keep that "canon" little "safer" .

[FrankRizzo]

Did anyone see "Artillery Games" on the History Channel last Friday night? It was a damn cool show where various homemade cannons and mortars competed for distance, accuracy, efficacy, etc. They showed the effects of various types of ammunition (grape-shot, cannon balls, bar shot, etc.) against "human" targets, which was pretty impressive.

At the end, the winner of the accuracy competition pits their cannon against modern US-Military artillery @ 1000'. It's actually quite impressive. Although the modern cannon has HE rounds, it fails to hit the target even once (looked to be a 4'X8' sheet of plywood with target painted on). The replica cannon hits it 4-of-5 times within the bull's eye.

[Jacks Complete]

That's probably because the range was too short! Modern military artillery is very accurate, right out past the 5 mile mark. At 1000', it must have been near vertical, and hence wind affected lots, or else it was direct fire, at a flat target, which it should have been fine with, since they shoot tanks like that.

[Vinci]

I´m sorry for posting in such an old thread, but I have problems finding a good pipe. Even Austrias biggest metall-concern didnt had anything above 5mm wall thickness...

I just found rods in any thinkable size, but how to drill such a deep hole in it ?

[mediumcaliber]

There are books that should be in the ftp that cover deep hole drilling, and one website that briefly describes it is riflebarrels.com , although there are probably a lot of others. Use Google.
It can be HARD to find a supplier for thick walled seamless alloy tube, but they exist. One large one here in the states that has nearly ideal tubes for 20-50mm guns is very large but specialized in tube and bar supply. There should be several manufacturers in Austria and Germany that make these sorts of tube -a lot of seamless tube technology was invented in Germany- and if it helps, I believe I've heard of a European machine shop referring to such stock as hollow bar.

[Vinci]

Ok, finally found a company wich sells nice tubes, but now I´ve a problem to choose a diameter.

I thought about 95x20 (everything in mm) or maybe even 115x20. Of course it should stay somehow portable and the price is important too...
I´ve no clue what 1m of such a pipe cost here.

Here´s a nice list of the pipes they sell:
http://service.rohrmertl.at/liste/ll_s.htm?SPRACHE=D

[tomu]

Well, you'll have to be very lucky if the pipe dealer sells you just one metre length of the pipe you want. Normally large dealers like this sell only full length the pipes are manufactured which are 6 metres or sometimes 3 metres.

A pipe with this measurements isn't cheap, my guess is about 100 Euro plus/minus 20 Euro per metre, more if the dealer just sells you one metre with an additional charge for cutting the pipe.

[mediumcaliber]

-------------------------------------------------------------
EDIT: Looking at the website... the tube spec turns out to call for low carbon steel, yield strength 345 MPa. I guess you mean that the walls will have a thickness of 20mm, which makes more sense than a 20mm ID. You're talking about some very heavy stuff with a 95mm OD; 37kg for a 1m tube... How do you plan to transport it? I would advise going with some kind of alloy tube if you can find one, because the strength will be 2-3 times as high for the same weight, and it's said that it's about the same cost per total strength. With a 95x20mm pipe, it will start to yield at only 184 MPa, about twice shotgun pressures, so you'll have to watch how much powder you use very carefully. I heard of some guys firing a blank load from a homemade cannon not too long ago and killing themselves when it exploded.
One way to avoid this might be to put a strain gage on the tube and measure firing strain; they have equipment to do that with rifle barrels here for $2-500US.
Edit again: That dealer does have 20MnV6 hollow bar (Maschinenrohre), which is still low carbon (.2%) but with some vanadium doping, and it can supposedly be heat treated to 620 Mpa yield, which is still not optimal, but a bit better.
http://service.rohrmertl.at/liste/ll_m.htm?SPRACHE=D
http://www.interlloy.com.au/data_sheets/hollow_bar/20mnv6.html
--------------------------------------------------------------
What alloy? You can probably get some idea what the alloy costs and find the weight of your tube. I seriously doubt you'll need more than one bore diameter of wall thickness to be safe with just about anything. It's almost difficult for conventional guns to reach 100KSI (100 K PSI) pressure, and if your tube OD is twice the ID, the tube will withstand internal pressure equal to the yield strength of the material. Since a safety factor of 2 is advisable, then if you can find a *reasonably strong steel,* the OD shouldn't need to be more than 3x the ID. In US terms, high end maraging steel has yield strengths from 250-350 KSI and mild steel more like 30-50 KSI, while types 4130, 4140, 4340, 8740, and a number of other low alloy steels can easily be heat treated to above 100KSI.
In more expensive products like this, I think dealers will be willing to cut off however much you want, at least in America. The dealer I know of offers custom cutting and related services to go along with their steel.

[Vinci]

Ok, so 20MnV6 is the way to go ?
I still don´t know wich diameter I should choose :D
And what about the lenght ?
On what does it depends ?

On the diameter ?
The used propellant ?

/edit
how much can stand a DOM pipe with the same diameter ?
I won´t take any risc of exploding pipes !
but where to get them... :/

[tomu]

Ok, so 20MnV6 is the way to go ?
I still don´t know wich diameter I should choose :D
And what about the lenght ?
On what does it depends ?

On the diameter ?
The used propellant ?

/edit
how much can stand a DOM pipe with the same diameter ?
I won´t take any risc of exploding pipes !
but where to get them... :/

20MnV3 is a very tough steel and takes quite a lot of abuse.

What lenght and what diameter depends on what o you want to do or what type of mortar you want to build and what projecties you want to fire, also to what range and with what type of propellant.

There are two engineering formulas for calculating the burst pressures of barrels, but I don't have them at hand right now. If I will not forget I'll look them up and post them sometime.

But it's not only the maximum pressure but also the time-pressure gradient which plays an important role in the way a pipe bursts.

Obiviously you know nothing otherwise you wouldn't ask such questions. So I suggest you should only experiment with Black Powder as a propellant, because as long as the projectile is capable of freely moving in the barrel and as long as it isn't too heavy a heavy walled steel pipe will not rupture, but you can blow the bottom plug out if it isn't properly made.

I further suggest you make a trip to Ferlach and visit the Fachschule fuer Buechsenmacher and the Ferlach Arms Museum in Kaernten and have a look at their library. Btw. you can find a lot of literature about guns and arms in austrian libraries, so do your homework. If you can't find suitable books at the library in your hometown think about Fernleihe.

[Vinci]

Well, I red all the threads in the forum since I´ve no books about artillery at home yet. But the hardly contain any usefull information ...

I´ve searched with google too of course, but I want hard facts (formulas). And I never thought about any other propellant as blackpowder (maybe DBSP one day) because I´m not one of those idiots who use HE charges.

I asked for the length because I first thought about building a conventional cannon as I prefer low shooting angles. But as the cannon should stay somehow portable I´ve to find a good compromise in it.


/edit
You may show your knowledge by explaining the connections and showing some examples. (like such diameter, with that length and ... you know what I mean)
So, more technical, not just "5-6cal. lenghts are howitzer" or stuff like that.

[Vinci]

I´m sorry for making a double post, but I found a very interessting passage in Meyer&Köhler´s "Explosivstoffe" page 379. I´ll try to translete the text as good as possible:

"The, at the detonation of propellants, upcoming pressures in the inner ballistic can reach up to 600MPa and temperatures of 4000K. To calculate those pressures and temperatures a "condition-equation" is needed, wich connects the pressure, the temperature, the gas density and the specific molnumber."

Now there is a part about the equation, but I won´t write it down. Its pretty complicated as there are 2 virial-coefficients in it wich describe the increasing double and thirdimpacts on gasmolecules with the growing gas density...
The calculation of those virial-coefficients has something to do with statistical thermodynamic...but lot more complicated than usuall thermodynamics with explosives... ok, nevermind.

The next passage is way more interessting:
"The upcoming pressures from a detonation of a liquid or solid explosive after the shockwave can reach 2-50 GPa and temperatures of arround 5000K."


That should explain why high explosives (to be exact: detonating HE) can´t be used as propellant. (I wonder why keith got banned ? Was it because of that thread ?)


/edit
maybe anyone can find more informations about the calculation

[mediumcaliber]

It looks like you have a lot of reading ahead of you :) I have an English ebook of Meyer, Kohler "Explosives" 5th ed, 2002, and I'll look in it for what you referred to on propellants, but, if you don't aready know, plenty of propellants and HE share common ingredents. HE compositions are optimized to detonate, while propellants try to avoid doing so; RDX is common in HE as well as LOVA propellants where, if I understand correctly, a binding system was meant to reduce sensitivity, as well as some older missile boosters. Is there a word in German for 'deflagrate?'
-----------
What heading was the entry in Meyer under? My copy is encyclopedic and probably has the same segment in a different place.
----------
I had a theory that might be useful in estimating very roughly how much of a propellant of known qualities might do what; but bear in mind that it probably has an error in excess of 10% charge mass and that experimentation with reduced charges and some means of determining pressure is necessary. It should give a very general idea of the charge size.
http://www.obscure-reference.com/cgi-bin/atr.cgi?read=776

A short paper that goes over better interior ballistics theory in a little detail is
http://handle.dtic.mil/100.2/ADA076175

[Vinci]

Of course, thats why I wrote detonating in anchor. And ya, there is a word, its just "deflagrieren". I´m not new to explosives, just to cannons.
--------------
The headline is "equation of state".
--------------
The book contain a lot of usefull informations about thermodynamic calculations, not only for explosives. But the thermodynamic section in the book only contains explosionheats, gasvolumes, oxygenbalances, and and and... well known calculations at all.
Not exactly cannon related :/
But maybe can you figure out how to calculate the pressure ;)
--------------
I wonder if its even possible to calculate the propellant amounts for a homemade cannon. There are just too many facts you would have to look at... (just for example: the quality of the propellant won´t allways be the same, that gets even worse when using DB propellants like NC/NG)
I guess its only possible to estimate it or doing some trial&error and start with little amounts.
--------------

/edit
ah sry, you allready mentioned, I should red the whole post next time before I write my answer
nice links you´ve found there

[dana_m_h]

My cannon is roughly 2.5" in diameter... just the perfect size that it made it impossible to find any ammo. A can of tomato paste is just a hair too large... but a shot glass is a hair too small. i ended up wrapping a large bouncyball with 2 rolls of electrical tape. I used a film canister of FF grade pyrodex for the charge and typical cannonfuse for the ignition. It went off a little larger than I expected with a huge thunderous BOOOOOM echoing for atleast 20 seconds in the valley I fired it. The velocity must have been in excess of 500fps but I am sure it was less than 1000fps because there was no crack to it..... I dont think at least. with my fingers in my ears they were still ringing after i fired it. Some time when the Local Yocals ( area pigs ) calm down I will do it again. This time in the daylight. I was supprised that there was very little muzzle flash. But the amount of smoke was quite large. what would be a good ammo to use so I dont run out of electrical tape again... thanks in advance

-------Just Another Henchman

[Dank$taVegas]

My cannon is roughly 2.5" in diameter
A pop can is roughly 2.5" in diameter around the center of the can, you could drink the pop from the cans and find something to fill the empty cans with, maybe some cement or something similar.

I personally don't have any experience with cannons thought so this is just an idea.

[ak-47_gunner]

I have a .70 cal 1 ounce slug mould
made a cannon from hydrolic cylender tube I have put it through over 6 inches of solid pine at 20 feet using rifle powder

[dana_m_h]

a pop can is roughly 2.75 in diameter like a tennis ball both are too big and a golf ball is too small