40mm Practice Grenade Conversion

[nbk2000]

Getting a working 40mm grenade is near impossible, and highly illegal, thus not worth the effort.

However, the inert practice rounds are readily obtainable. I got mine for $5, including the nylon case and spent (but reuseable) propellant shell. :)

As seen in this cutaway view, the orange dye powder takes up the majority of the space in the practice round. The blue shell is made of a brittle plastic that shatters on impact with any firm surface.

<img src="http://nbk2000.freeyellow.com/Grenade_40mm_Practice_Cutaway.jpg" alt=" - " />

This hollow space is about 25ml in volume in the grenade I dissassembled (below) and could easily be enlarged by boring out the base to remove most of the metal, as seen in the picture above.

In this close-up view, you can see the orange powder at the edge of the shell. The soft aluminum driving bands are immediately below the blue shell. These engage the barrel rifling

<img src="http://nbk2000.freeyellow.com/Grenade_40mm_Practice_Exterior.jpg" alt=" - " />

To open the grenade, I used a chisel to gently work my way around the casing, without breaking it. Once opened, I removed the fluorescent dye and the interior spring. Apparently the purpose of the spring is to ensure the casing splits open on impact, rather than staying intact like a fractured eggshell.

<img src="http://nbk2000.freeyellow.com/Grenade_40mm_Practice_Internal.jpg" alt=" - " />

Once you've removed the powder, and bored the base, it'd be simple to line the interior of the shell with BB's, and fill the void with a cast explosive. The hollowed base would contain the fuse, either a pyrotechnic delay as simple as a coil of cannon fuse, or as complex as an IC impact switch.

If you simply replaced the powder dye with a powered agent like CS, or a liquid agent like GB, you could dispense with any fusing since the shell would break upon impact anyways. :)

<small>[ January 20, 2003, 05:00 PM: Message edited by: nbk2000 ]</small>

[Zyklon_B]

Here, info on reloading those nylon cases:

<a href="http://www.okiebigbores.com/40mminst.htm" target="_blank">http://www.okiebigbores.com/40mminst.htm</a>

[Kriegsminister]

This is a simple method of conversion using impact ignition:

The impact primer would be a .223 rifle shell (remove bullet and powder, smaller ones might also work) filled with a suitable primary, such as lead azide. Now a hole is drilled into the top of the grenade body which the shell fits into. Now a small piece of cork with a hole in the middle is glued to the base of the shell. This piece of cork is used to hold a small nail which acts as a firing pin.

This construction is now securely glued into the hole that was drilled into the grenade body.

The next step would be to fill the remaining space of the grenade with some high explosive. You could also add some shrapnel...

If the grenade now hits a hard surface the nail will hit the primer of the shell containing the primary. The primer of the shell sets of the primary which in turn sets of the main explosive filler.
It might not be completely safe, but it should work and is very simple.

Here is a sketch:
<a href="http://www32.brinkster.com/bitchfresse/40mm_conversion.jpg" target="_blank">http://www32.brinkster.com/bitchfresse/40mm_conversion.jpg</a>

(Copy and paste the link!)

<small>[ January 21, 2003, 06:08 AM: Message edited by: Kriegsminister ]</small>

[Zach]

I don't think that I want to put my trust on a falling nail. A chemical fuse would be nicer.

[ossassin]

Instead of using training rounds, why not use something that already has a fuse? like a smoke canister?

<small>[ March 06, 2003, 06:11 PM: Message edited by: ossassin ]</small>

[blacktalon]

Sorry to disagree with you NBK, but grenade launchers are not actually illegal in the United States. As long as you are at least 21 and have a clean criminal record, anyone can own one. It is classified as a destructive device, (no shit right) and all you have to do is find a "class 3" firearms dealer with a dd permit in your state. He will handle the paper work for you. After your background check is completed, the application will be sent to the BATF along with a $200 "tax." Around three months later, the paper work will come back and you will be authorized to possess a real live 40 mike mike. The price is a little restrictive, (about $10,000) but it is possible. The same goes for machine guns, silencers, sawed off shot guns, and AOW's. A friend of mine has a legally registered Browning 1919 belt fed machine gun, as well as a sten. It's pretty cool stuff if you can afford it.

<a href="http://www.autoweapons.com/products/products.html" target="_blank">http://www.autoweapons.com/products/products.html</a>

Scroll down a good ways. There are several transferable M203s on there.

<small>[ April 09, 2003, 09:43 PM: Message edited by: blacktalon ]</small>

[nbk2000]

For someone who's been registered more than a year, you seem pretty ignorant of my point of view as regards the law. :p

Yes, Virginia, you can get a 40mm with all the BATF permissions, tax stamps, fingerprints, yada yada...but then what?

You could never use it for its intended purpose because "they" <img border="0" title="" alt="[Wink]" src="wink.gif" /> would immediately be looking for your ass, since you were so kind as to go through their hoops to buy it, telling them that you bought it.

Also, BATF has a bad habit of fucking over people who buy these sorts of things, regardless of the paperwork you have from them. Many class 3 dealers have been set up by BATF, then coerced into providing false witness against other dealers (and buyers), with the threat of decades in prison being the stick.

No thank you.

Besides which, even if I wasn't a felon (notice I didn't throw "ex-" on there :D ), I still wouldn't want anyone to know that I had these sorts of things. As a constitutionalist, I believe that the government has NO right to impose ANY sort of taxation or restrictions on man portable infantry weapons.

The Second Amendment was intended to ensure the right of the population to be able to defend against foreign and domestic tyrants by ensuring a massive civilian population (militia) armed with the weapons of the day. In the 1700's, that was a musket or kentucky rifle. Today, it'd be SLAGL and Javelin.

Heavy shit like tanks and artillery would still be the domain of the small standing professional army that the founders intended, rather than the bloated tick of almost 2 million we have now.

If the government knows you have it, they can take it away, which defeats the whole purpose, now doesn't it?

Thus, since you can't buy it legally without bullshit paperwork, that means you'll either have to make it or steal it, both of which are highly illegal. Hence the reason why this is in an improvised weapons forum...to improvise weapons you can't legally buy, see? :)

Also, who's going to sell you the HEDP ammo for your legal 40mm? Last I checked, there were NO suppliers willing to do so to non-military buyers, because of liability. And, the last time it WAS available, it was almost $300/round! <img border="0" title="" alt="[Eek!]" src="eek.gif" />

[HypersonicGamer]

I agree...

The Form 4 paperwork pertaining to the NFA firearms is a real pain in the ass - and the BATF usually take their sweet time in going through all of it. The reason lies partly in the liability for the manufacturers - they won't make possessing one of these weapons cheap.

Concerning the ammunition, training rounds are everywhere, but who wants training rounds? The actual HE grenades are taxed as DDs as well, so basically your shooting off an expensive tax stamp - plus, who wants to be liable for selling you the damn thing? These constraints are going to be strung so tight one day, that NFA weapons will cease to be in the hands of civilians. You'll be lucky to get a slingshot in ten years, let alone a grenade launcher. The prices increase due to the '86 law and has cut out a lot of people who want something besides a MAC. :rolleyes: Even the prices on Stens are getting to be outrageous - people resort to making their own. You can't go to any gunshow without hearing people bragging about how they put together a Mac or a Sten. There is also a high demand for NFA weapons - the idle rich have the money, and buy them at any set price.

Maybe the real problem is supply and hoarding - large dealers having an excessive supply and letting some trickle out. Lets say there is a dealer with 2000 Macs sitting on the table and can sell them for $1500 a piece or maybe he will want to be a nice guy and sell them for $800 a piece? What do you think he'll do... Heh, a nice 2000 Macs sitting on a table ready for some pre-mades to be produced. If he is running his own business, he is going to try to rack up all the money he can get. So again we are back to demand and hoarding - if you take a look at the price of some of this, it's damn near inflation! Heh, I'm sure there are still RDIASs and Registered HK sears still being horded. Remember when the AWB came into place? AR-15s went from around $600 --&gt; $1000 OVERNIGHT. LOL - I bet an M16 would cost around $850 without the NFA act. The other problem is the GCA firearms that never made it into the registry. There was a loophole...pre-ban magazines could be imported from other countries. Clinton closed it up, it went against the "spirit" of the AWB and poof - no more AK waffle mags (maybe a few crawled in a few months ago...)

The BATF CAN and WILL screw you over as NBK had stated above. They will arrest you, set an excessive bail, have better lawyers in court, have bigger bubbas in the can, and spend all the money they can to get a conviction.

I hope the AWB sunsets in 2004...yes...AK-47s will flood the streets again. :D

[blacktalon]

Yes NKB, I actually agree with you 100,000% on all accounts and your opinion of the government and laws is similar to my own. I was just pointing out that it is not actually "illegal" to own a 40mm. I never meant to sound like the BATF wouldn't screw you with the information you send them. It is just a common misconception that machine guns, dd's, sawed off shotguns, silencers, and switch blades are all together illegal for everyone(thanks to the media and movies), and that annoys me.
Everyone makes the argument that our forefathers did not have things like machine guns, so they couldn't have been talking about things like that in the second amendment. Well as far as I see it, our forefathers had muskets, and the British government had muskets. It was a level playing field. The attendants of the second continental congress just came out of an tyrannical government and they wanted to prevent that from ever happening again, which would mean the people must be armed, thus allowing them to rise up, (back in the days before everyone's mind was turned to mush anyway) and overthrow anyone who wanted to take our liberties. For that to hold true these days, one would have to be able to go down to the local sporting goods store and buy a TOW with no line and no waiting. The second amendment was not written to protect your right to duck hunt! (Pretty much as you said, but that has been an argument I have made for a long time.)

Anyway, this weekend I am going to a machine gun show, which sells machine gun parts. You can also buy 40mm m203 and M79 barrels with no hassle. :-) They are fully rifled and are in most cases new. If a person could some how "manage" to get their devilish hands on one of these, one could theoretically make themselves a simple action and have a 40 that was much more accurate than the smooth bores most people fabricate. :-)

Lastly, I have seen private individuals with legally registered 40s firing HEAT ammo. You need a type 21 (I think... not sure of the #) license for that and you have to have a concrete magazine to store them in just like any other legal explosive. If Bill Gates decided to jump through the hoops he could buy a fully stocked Destroyer. :-)

[nbk2000]

And someone really creative might be able to swap the barrel of a 37mm "look-alike" underbarrel mounted flare launcher with a real 40mm barrel to make an M203. <img border="0" title="" alt="[Wink]" src="wink.gif" />

Then, with "harmless" training rounds that have been converted to lethal fragmentation grenades, you'd have something serious to play with. :D

I saw a place selling 80% MK19 receivers for about a thousand. If only a person had a schematic for building one of those... :(

I've always wondered what was to stop a terrorist group from simply taking a shitload of advanced weapons from one of the contractors that builds them? While heavily defended, from a civilian perspective, the contractors are quite unprepared to defend against a military style assualt...with no lethal electric fences, minefields, claymores, MG defensive fire zones, etc to repel a group attacking with explosives or CW.

And the locations of the companies that build things such Javelins and MK-19's aren't secret. 'Course, this would be a one-time thing, since everyone else would be armed to the teeth thereafter in anticipation of being next. But you'd only need to succeed once to become a very serious threat.

[DaRkDwArF]

Hell, Imagine storming the creaters of metal storm or the OICW and arming your cell with weapons like that, they maybe small arms, but their 10 times the small arm then what the piggers are going to pull on you. Launching a 20mm shell into a piggers squad car just as they roll into the driveway or unleasing 4,000 lead slugs into an entry team just as they bust down your door... oh the possibilities....

[Flake2m]

While I would agree that th BATF would probaly screw you if you did own a 40mm grenade launcher.
The government make you register guns to stop people from having there own armories and turning neighborhoods into urban battlefields.
I am pro gun but I do believe that if you own you should have the common sense to know when and how to use it. I am guessing 90% of the forumites here dont want an there neighborhood becoming a battlefield 4 days a week.

As for the grenade launcher, I wonder if a "training round" could be converted to carry a WP payload? Or at the very least you should be able the replace the orange powder with pepper spray.

[A-BOMB]

You can get the 1/4 ounce HE round that they use for training they are legal because of only 1/4 ounce of comp I think? saw something about it on <a href="http://www.37mm.com" target="_blank">www.37mm.com</a> some one was selling them on gunbroker.com or actionarms.com

[blacktalon]

While at a gun show over the weekend I found a couple of suppliers of actual rifled M203 barrels. No paper work, no questions, no hassle. I believe they will even ship. The first guy's barrels were new for $350. The second guy's were used in excellent condition for $195. The second guy however, had sections of rails. With a couple of those rails you could fit a simple action to a pipe or a piece of stock, weld it up and you would be ready to rock. Here is their info:

Dennis A Todd
Law Enforcement and Collector
Auto Weapons and Destructive Devices
FFL Class 1, 3, 10

540 Baltimore Pike
Springfield, PA 19064

610-543-7300
Fax 610-543-7909


Neal Smith
Class III Firearms and Destructive Devices
Gatling Guns and Hotchkiss Revolving Cannons
Safari Double Rifles and Big Bore Rifles
Buy-Sell-Trade

8205 Lakeshore Blvd.
Mentor, OH 44060-1418

Phone And Fax
440-257-4872

[Felonous Monk]

nbk2000 you mentioned in one of your posts that it would be nice to have a schematic for the MK-19 or H&K's GMG. As there aren't any readily available it seems that prudent thing to do would be for the Rogue Science Forum to design it's own.

The first order of business would be to decide on a standard piece of design software, for example MasterCam, AutoCad, BOBCad, CadKey, etc.. However recent reading on my part suggests that Solid Works would be an ideal software package for this sort of application.

Secondly the desired parameters and characteristics of operation would be discussed, agreed upon and then more or less set in stone.

Third; Either a standard munition and link system would be adopted, or the Forum would design its own perhaps optimized for expedient manufacture. Swaged and pressed Copper pipe might be found suitable for this purpose.

Fourth; Once the munition envelope is decided upon, the feeding and extraction mechanism could be developed.

Fifth; The Bolt or Breech Block and it's element that communicates with fourth system developed. It would seem that the bolt is the source for much of the weight in the Mk-19 as it appears to be a straight blow back system.

Sixth; the fire control system(safeties,trigger, hammers strikers or sears etc..) would developed alongside the Bolt.

Finally the Receiver including it's ergonomics, aesthetics and importantly the marriage between it and the barrel. The Mk-19's barrel is said to not overheat under prolonged firing however it would be wise if any designs included provisions for quickly changing hot barrels.

If you're interested post your thoughts and we will see if there is sufficient interest to warrant continuing a disscusion in this vein.

[I_am_the_Black_one]

Hell yes mate im interested in your idea im only a amateur at weapons but i still think I could provide help. I just hope this idea takes off. Do you or any one else have the software to do this . Also I think it would be a bad idea to associate this with The forum

[Felonous Monk]

The Software is really not a problem in terms of people being able to get their hands on a decent CAD tool. But in insuring everybody involved is using the same one. In terms of actually getting the project started it doesn't appear that there has been enough interest to get things going. In my opinion this is precisely the sort of project that is appropriate to develop in the forum. For example my experience deals mostly with mechanisms and design, I lack the knowledge from a chemistry standpoint to develop quality munitions, though I could probably design a swage set that could form shells. Hence the Forum, where else does knowledge and interest coincide?

So let's give this a try.

I suggest that any design developed use a delayed blowback system to reduce its compared to the americain and german models.

[zaibatsu]

This subject interests me a lot, as I am quite interested in firearm mechanisms and methods of production, especially expedient :)

The first thing I wish to establish - how expedient do we want to go? Producing the propellant? If so I suggest the AN propellants developed in the late 19th century - we can make it and produce it with more repeatability that we could smokeless powders.

Also, I think belt-feeding would necessitate a rather complex mechanism. How about increasing portability and have it drum fed? Then again, the diameter of the grenade would make this a little difficult - how about reducing diameter to 30mm or so?

I hope to purchase a book on operations with dies, and is supposed to have a section on cartridge shells which could be very useful. Also, primers could be punched and filled with a chlorate comp.

We'd probably have to produce our own barrels - shouldn't be too difficult for a smoothbore. And if we use the high-low pressure system of the 40mm shells then we could perhaps use DOM tubing for the barrel.

[nbk2000]

It'd likely be easier to use electric motors and cams instead of designing a recoil operated system, since a home-made doesn't have to be as durable as a military weapon that has to endure abuse on the battlefield by lazy soldiers.

[Felonous Monk]

An electric motor (modified cordless drill?) turning a crank connected to a rod driving the breech block with a slot let into the end of the rod would allow the breech block to pause and lock at the end of the cycle. a cam wheel like in gatling guns could also drive the bolt. or perhaps slightly more compact then the previous two options; a cylinder with a continuous groove cut in it the groove having an opposite or reversing pitch so each complete revolution would provide one forwards and backwards movement.

A drum magazine seems like a sensible alternative to designing a belt feed system, in terms of propellants and primer's I cant say i've given it much thought. Originally I was thinking along the lines of commercially available reloading supplies, but a Forum specific system has its own appeal, being adaptable to all political climates(hopefully).

In terms of design software any suggestions; I can work in AutoC*d2000, BobC*d, MasterC*m/C*d v9. preferably MasterC*M if anybody expresses interest in either the project or the software perhaps it might find it's way onto the FTP.

But if this is going to continue we should sort out at least the preliminary data for the munition.
Zaibatsu, your suggestion was 30mm o.d., Im amenable to that, i'll see what I can work out, but i can't guarantee a reasonable result as i've done any design remotely like this.

[zaibatsu]

A mechanical crank system would make it less susceptible to problems caused by expedient munitions - variation in the amount of propellant would vary the recoil, which would cause problems in the straight blowback system. But I think it might over-complicate matters, a blowback system would have less exposed parts and absorb some of the recoil. My suggestion would be simple blowback, just like an early smg.

Regarding the 30mm ammunition, that was only a suggestion. However, I think it is important to define what would be the purpose of such a grenade launcher - AP? AA? OR a general purpose weapon? Naturally the AA role would only be effective against light vehicles. Normal reloading supplies such as smokeless powder and primers are available in the UK, and therefore it's reasonable to assume the same is true of Europe, so it would be possible to design around these. However, any other components such as casing or shell needs to be homemade, as there is very little chance of purchasing these in the UK.

Whatever software is best for you is what I'd suggest we should use - I personally have no experience in this field and therefore it would be nice to have someone to provide advice.

[Felonous Monk]

sorry for the delay in replying, tried to upload some software last evening, but it didn't go so well. Trying again today. I believe we should aim for a general purpose machine capable of feeding and firing a variety of cartridges that fit within a certain parameter. spent some time today doing some net research at www.corbins.com. despite the commercial nature of the sight I believe at least some knowledge there of value. If anybody has a copy of their bullet design software it would be interesting to model any proposed designs.
so with any luck look for a file entitled
"MasterCamV9 uploaded by felonousmonk second attempt.ace" it should be 130mb. I'm afraid i wasn't able to resume where i left off before hence the new file. So ctrl_c (if you read this) you should feel absoulutely no obligation to the first file except maybe to delete it.


hope to post some actual content soon.

[nbk2000]

The original 40mm machinegun was a hand cranked version that used interlocking lobed gears to both feed/eject the casings as well as form the firing chamber. Though this might require rather complicated machining. :(

Something that could be made would be to use DOM tubing to form both the grenade body, as well as the propellant casing, by using a base plug in the grenade that fits tightly into the propellant case. The bottom of the propellant case is sealed with a plug too, but this one is flush fitted. Since this is an improv device, no reason not to use electric ignition, rather than primer.

This would be suitable for AP only, I'd think, unless you can design a reliable SC that'll fit in such a small casing.

[wrench352]

I will be uploading FM 3-23.27 MK-19 40mm grenade machine gun,mod 3 to the ftp shortly.Nov 03 edition.I hope you enjoy,

[12Gauge]

For anyone really wanting to obtain an m-203 or m-79 type weapon, in Canada they are not regulated at all- not even considered to be firearms, for that matter. Actually, this is also true for real artillery. I've seen M-203 and similar launchers here for around $2500-3000 Canadian dollars. Pretty expensive for what they are, but now the US state dept won't allow export of Class 3 weapons for use by civilians....you have to sign an end user certificate to get a AR-180B for christ sake....values on the launchers in civilian hands will undoubtably go through the roof- much like the machine gun prices in the US

[keith]

If you had a good friend in the Marines he could get one for practice and "loose" it and simply pay the $480.00 replacement cost that Marines pay when they "loose" iteams. MY cousin can get me one but I'd rather make it for under $100. Single shot 12g shotgun with barrel removed and a 40mm DOM tube in its place. Rehook the new 40mm barrel to the drop hing the 12g barrel was afixed to and there you go. The fireing pin will be perfectly centere if you doit right. You might have to mill some of the shotguns action away right under where the 12g barrel was and fabricate a thing on top of the barrel to hold it closed (I am going to use a remington single shot 12g. cost $75 for the gun and $40 for the 40mm DOM tube.
Also, I'd use blackpowder instead of smokeless liek teh military uses because youd only need about 60grains to shoot a 40mm canister about 300 yards and it wouldnt make hardly any noise. And almost no recoil :)

As for a HE round, what about filling the round with NG. NG can easily handle the G forces of launch without detonating yet on impact it would detonate. I tested some of my NG that is about 3 months old by puting alil bit on a tissue and clamping it in my huge vise and putting about 500 pounds of pressure on it.....nothing happend. I then took that same peice of tissue and struck it with a hammer.....BOOOM
Maybe this is too dangerous though.

[grendel23]

The problem with using NG in the way you propose is a property of some liquid explosives called "sensitivity to adiabatic compression".
If there is a small air bubble (and you have no way to know there isn't), the shock of firing will compress the bubble, heating the air inside and detonate the explosive.
Just dropping a bottle of NG on a hard surface can cause an LVD.

Using any explosive in a hand fired weapon is very dangerous, NG would be suicide.

[xyz]

Errr... If NG is suicide, then why do we have double base smokeless powders that contain it and why did the cordite in old .303 rounds contain 60% NG?

Pure NG may be suicide, but mixtures of NG and NC definitely aren't.

[Blackhawk]

The NC I would assume would significantly de-sensatise the NG, enough for use, that and that it would be a more solid gell rather than a liquid (blasting gelatin?). The point of what grendel23 was saying (I think) was that keith was considering using NG as the HE head of his 40mm grenade, which as grendel said would cause significant sensetivity problems with the accelartion experianced, problems you wouldn't get with a .303 as the NG mix is supposed to go off in the chamber ;)

[grendel23]

xyz, I didn't intend to state that any use of NG is excessively dangerous. I have made and used it myself and have found it to be quite safe if made correctly and given the respect it deserves.
Blackhawk is correct that my main point was that pure NG is much too sensitive to be used as the HE charge in a grenade to be fired out of a launcher.
There are many explosives which could be fired from a launcher, TNT, ammonium picrate, and yes you could probably use some form of NG containing explosive such as blasting gelatin.
The hard part would be coming up with a fuze or detonator that would detonate the device on impact while never blowing up in the tube.
This can be done, I belive the military devices use the setback at firing to arm the fuze, But I would not want to fire an improvised version from the shoulder.

[Skyscraper]

What exactly is the purpose of this 40mm grenade? I'm pretty sure that a 40mm buckshot round, which would be much easier to make correctly, could disable any vehicle up to an armoured car, and would still be good at closer ranges with no risk to the user.

[keith]

Well I stated that I absorbed the Ng in a tissue. So it wasnt pure. I didnt think about the whole air bubble compressian thing that you mentioned and I dont know much about it but I do know that I put atleast 500lbs of pressure on the Ng when I put it into my table vise and nothing happend.

I have a Mac. not a windows so it's kinda hard to post pics or anything due to different softwere and stuff but if I could work it out or post from my friends computer, would it be alright if I were to post some pics of my 40mm Grenade launcher made from a single shot shotgun? any mods mind? This thread inspired me to finish it and so I did. I have yet to buy practice rounds so I havent tested it yet but it will work beautifully.

[kingspaz]

pictures say thousands of times more than words, go for it!

[Anthony]

You can't rely on the shock sensitivity of NG to make a round detonate on striking the ground. Even if it did work (it'd be very unreliable at best), you'd probably only get a low order detonation. You need a proper detonator.

Also, NG soaked into tissue paper is just that - pure NG held between the paper fibers. It's not a mixture like blasting gelatin.

I'd also bet that compression in a vice and launching shock would affect explosives quite differently.

skyscraper - is 60 grains of propellent going to propell a 40mm buckshot load effectively? If you have to up the powder load, then surely you have a canon, not a grenade launcher? :)

[keith]

I would use black powder because 50grains can propell a firework that weight about a pound 300 yards up. 100grains of BP is plenty to propel any grenade as far as you could want it to go. Muzzle loaders use about 100grains so the recoil would be similar to that. Another problem is getting the smokeless to detonate. Ive made homemade shotguns that still used normal shotgun shells and homemade rifles taht use real rifle bullets but the didnt work.I finaly relized that if the projectile isnt tightly in the barrel you run the risk of the powder only burning. Smokeless powder doesnt make enough gas to shoot the projectile if it only burns. NC and NG are in smokeless powder so compare teh differences between detonation and deflaguration with these HEs. And 60-100grains of smokeless powder is going to have excessive recoil with that heavy of a projectile.

By not pure Ng I ment it wasnt just sitting there. Sorry, shoulda been more specific. It was soaked up in cellulose(isnt that what cotton and tissue is?) to keep it from getting air pockets and to de-sensitize it slightly. I know slow presure in a vise is different than a shock,thats why I tried that test. When the projectile is launched it's more like a slow steady pressure rather than a quik shock so it wont detonate apon fireing yet when it hits, its more of a quike shock. But as Anthony said my idea isn't very reliable.

[Anthony]

Smokeless powder does not detonate in normal use. It does however burn more rapidly under pressure (like many large rocket propellants). So if you have a loose-fitting projectile, the chamber pressure won't be very high, meaning the SP doesn't burn very fast, making things worse.

[keith]

But either way a loose fitting projectile wont work with smokeless like it will with black powder right?
Can blackpowder ignite magnesium ribbon? You could make tracer rounds for teh grenade launcher.

[xyz]

kieth, just because it uses the same powder quantity as a muzzleloader it doesn't mean the recoil will be the same.

Compare a .223 to a 12 gauge round, they both use similar amounts of powder but the 12 gauge kicks much more because it is pushing a much heavier projectile/s.

A loose fitting projectile with smokeless won't work as well as a loose fitting projectile with BP. Smokeless needs more confinement to burn at it's proper rate.

Why would you want tracer rounds for a grenade launcher :rolleyes: ? The purpose of tracers is so that you can see more clearly where machinegun fire is going, you should be able to tell where the grenade went :rolleyes: . The only thing useful about them would be the firestarting aspect but then you may as well just make an incendiary round.

[keith]

Ilumination rounds would be very fun at night. Yea I understand that the projectile weight has alot to do with recoil. My main point was that black powder would be a better propellant choice for grenades. 40mm is the same diameter as my howitzer.
The tracer round was just a for fun idea. Surves no combat purpose but your not going into combat with this are you? If you are I wanna come. I've always questioned the effectiveness of the 40mm grenade launcher because of it's accuracy problems and it's small blast radious. Standerd infantry grenades have a kill zone of 5 meters and an injure zon of 10. The 40mm grenades arent any more lethal than these. How close do you think you could land a grenade to your target at 200 yards? Probably fun to shoot though.

[xyz]

Make that an injure zone of 15, and it is only the RELIABLE injury zone, grenade fragments are fully capable of killing someone 200m from the blast, but it is unlikely due to the extreme dispersion of frags at these distances, still, that's why you get behind cover after throwing/launching a grenade.

Smokeless powder will work better than blackpowder, you just need a projectile that is the right size for your barrel.

[PHAID]

NATO specs on all modern grenades states that at 20m there is basicly no chance of a lethal wound.
At 0-10m your probably dead and at 15m your wounded.
Defensive grenades have a slightly bigger blast radius.

[Skyscraper]

Originally posted by Anthony
skyscraper - is 60 grains of propellent going to propell a 40mm buckshot load effectively? If you have to up the powder load, then surely you have a canon, not a grenade launcher? :)
Maybe you do, but is there something wrong with a portable cannon? It has all the advantages of a real riotgun, with all the compactness and versatility of a 40mm grenade launcher. Of course, if it were homemade, you'd need to make sure the extra powder wouldn't add too much pressure, but otherwise, I think it'd be for the most part more effective and safer than an explosive handload. One could also use it as just a really big shotgun, in places where punt guns are hard to get ahold of.

[DRDAD]

Maybe I missed it in the post but the fuse to the 40mm round is spin armed. Placing an impact fuse without this delay may lead to detonation of the round in the barrel with catastrophic effect. The other unintended consequence would be a UXO downrange. Not something I would want to have to go look for if it didn’t go boom.

[Dave the Rave]

Indeed it´s spin armed but it´s to hard to make it by improvised means. The best ways are a fuse that lits when the grenade is shot and the plain impact detonation.

Othewise, the spin lock to the detonator can be replaced by an improvised one where the inertial force of the fire of the round displaces a safety pin which holds in place another pin which rests against the barrel of the laucher. When the gun is fired, the inertial force pulls the safety pin backwards, releasing the other pin which is held in place only by the wall of the barrel. When the grenade lefts the barrel, the pin falls of it´s place releasing an spring loaded detonator that is then free to align with the firing pin.

I will draw an sketch to post...

Other topic, why not make an "handheld mortar" instead of the 40mm grenade laucher ? On my wet dreams it is just like an grenade launcher, where the case of the grenade is replaced by an 12ga propelled mortar. The reloading of the weapon is the same as the regular grenade, the rear of the weapon is open and the complete round is placed. The weapon is closen and cocked, then fired.

I believe that this gun is a good choice to homemade arsenals, cause the rounds are easily made, can be readily recharged by the means of one 12ga round without the lead and the payload of the projectile can be increased.

Again my verborragy cannot fully describe my dreams, but I will draw it and post, as soon as I find how to post an pic hosted at the ftp.

[Dave the Rave]

Here is my version of one reliable 40mm round.

With this design, there is no need of the case or the operation of unload the spent shell, prior to reloading the gun. By this mean, the rate of fire is improved.

Another nice thing on this design is that the payload can be bigger, as the propeling charge is more powerfull tha of the traditional 40mm lifting charge.

It uses a blank 12ga shell, with it´s full powder charge and, I hope, the recoill will be smaller than the kick of the shotgun cause the barrel is bigber, givin more space to the expansion of the gases.

forumftp.serveftp.com/hosted_images/40mmmortar.jpg

This second image is the inertial detonator.

In this design, the grenade remains inert till it´s shot, when it arms by the means of the acceleration forces over the inertial safety pin. After the dislocation of the inertial pin, the "gap" pin remains in spring loaded, but on it´s place by the means only of the wall of the barrel.

When the grenade lefts the barrel, the force against the "gap" pin ceases, alowing the spring to releases, and the pin "jumps" off it´s place, thrus freeing the way from the firing pin to the detonator´s cap.

The process then works as the usual, when the firing pin hits the target, the breakable pin is broken and the spring drivens the firing pin against the detonator.

forumftp.serveftp.com/hosted_images/40mmindet.jpg

[Jacks Complete]

Have we made an decisions on the CAD software yet?

Also, something no-one here has talked about, is that the reason grenades are only partly effective a lot of the time is because they are on the floor, and half the bits go into the floor.

Perhaps this beastie could throw some of the suggested "weebl" rounds? (Launching the Tetra Grenades NBK came up with would be a bit tricky, though.) This would mean that the blast could be a little more focused on where it counts, like at the legs of the body-armoured BATmen?

[Dave the Rave]

Yes, ideed JC !

But with my design, most of the fragments and explosive force are directed against legs and lower torso, because of the tail and fins of the grenade. Besides, my design is based on the mortars, so it can be modified to deliver shaped charges.

I am working on an improvised version of the "tilting" detonator of the "potatoe masher" , to use on the 40mm handheld mortar, so, it will became safer and will detonate as soon as the warhead find it´s foe... Or touches the ground.

As my images don´t open, I will post it here to download.

Here is the inertial detonator.

[Baughb]

Here's one idea for a spin-centric arming device. A tube is constructed in such a manner so that it spans the entire width of the 40mm round, with the center portion of the tube sealed off. On both ends of the tube are electrical contacts, open by default, and closed by a small ball bearing when it is in that position. Each end of the tube has a ball bearing placed in it, and a weak spring placed in behind it that holds the BB against the middle partition under normal usage. When a force is applied, the spring will collapse and allow the BB to contact the end terminals and close the circuit. A simple diagram would be:

_#_____________________#_
|======* |//////| *=====|
-#--------------------------#-

# is one side of the contact, * is a ball bearing of small diameter, = is a spring,
|, __, and --- denote walls of the device, and //// is a filler of your choice.

It would take some math & testing to figure out what sort of force the springs need to collapse under, but that's nothing too hard. This system has the advantage of not arming due to outside impacts, or exterior forces because any exterior force would cause only one of the arming bearings to hit a contact, where both are needed to close the circuit entirely. However, the centrifugal force imparted by the spin forced upon the round by a rifled barrel _would_ place both BB's at the arming position, in theory. I haven't run the numbers yet, and don't have the time or mental capacity to do it right now anyway, but if the round's spin produces a reasonable force, it'll be a fairly safe arming device.

Couple it with a miniature timer circuit, and you can have the detonator arm after X time of BB contact, allowing you to have the round arm X distance out of the barrel. The only downside I can think of right off would be that you'll lose a bit of room normally occupied by HE, but hopefully not too much.

[Jacks Complete]

Great!

Have to wait for a mod to authorise your download, though.

Another thought I had during a rather boring meeting was a dual warhead, which fired at (for example) T and T+2 seconds. The outer shell goes off, and takes out the legs (mostly) of those nearby (say a 35 degree arc, 360), then a second or two later, a more 2D layer goes (5 degrees, 360).

This way, the round sails up and over, goes pop, then, a few seconds later, after the injured have fallen, the coup de grace.

This is infinitely easier than a sensor to detonate while the round is x feet off the deck, yet should get the same result.

If we look to the OICW, we can see the way these things are going. Time Of Flight detonation is do-able, in an improvised munition, and is a resonable way to go which avoids the complexity and expense of integrating of accelerometers. This is achieveable by a simple timer circuit, with (of course) a single level inertial trip (something on a spring!) to start the timer.

As far as the 40mm round goes, does anyone know what sort of performance we can expect? I can load BP or Nitro, or (though I haven't yet tried) a rocket based system (or simpler base-bleed) could be used. These things are easily done by the "amateur".

As far as barrels go, is there a truely international standard for tubes/pipes which would let us all use e.g. a type of gas main pipe? Schedule 40 (US standard for water pipe, IIRC) doesn't exist in the UK, for example.

By the way, who is Tirany?

Added: I keep getting "Try again later, the server is too busy" messages, both when trying to post this, and when trying to get past the main front page!

Further: Warning: mysql_connect(): Too many connections in /hsphere/local/home/roguesci/roguesci.org/theforum/admin/db_mysql.php on line 40

New one: Warning: mysql_connect(): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2) in /hsphere/local/home/roguesci/roguesci.org/theforum/admin/db_mysql.php on line 40

[lumberjak5010]

Skyscraper
This info in strictly from my personal military experience in the field.The purpose of the grenade launcher round depends on which type of grenade launcher and which round. I was issued a 203 on several occasions and we used it for many purposes. One was parachute illumination flares to machine gunners could see them, to signal, or for general illumination. Smoke marker grenades of all colors for evac or targeting with forward air. Paint marker and practice grenade for local targeting and marking for small arty and TOW. Incendiary grenades to burn out and entrenched enemy or to set something afire like vegetation to create smoke screens. Anti-personnel grenades obviously for killing enemy. String grenades to span a crevasse so a rope could be pulled across and then a braided cable for personnel crossing. Wire grenades to drop commo wire across a gorge. Tear gas and chemical agent grenades. Whistle grenades who's function I am not sure of.
Air burst grenades which I never used or saw. HE grenades were useful in knocking down a protected road block or stopping a vehicle. And WP grenades which burned the heck out of stuff. One must be very careful with WP, it's very hard to stop once it gets going. By far, the most common was the anti-personnel grenade. One note: some times, if you fired the grenade a certain way, it could come right back and land in your lap before detonating.
As far as the discussion of effective range for a hand grenade, I noticed the baseball type grenades were very effective. Once that grenade went off, there was a ten or fifteen second period of time before hundreds of pieces of schrapnel came raining down on us which describes the range. I wouldn't want to be standing within 75 meters of a surface detonation of one. The fragments from the baseball grenades are of all sorts of shapes but seem uniformily sized from 3mm to around 20mm or so. They are very hot of course if you get hit with the initial detonation and some are quite sharp.Many factors determine the effectiveness of a hand grenade. The most important factor is the hieght above ground at the time of detonation. Most of the grenades I saw used detonated on the surface, in a hole or under a vehicle or some other object. If you got lucky and timed it right, you might get a grenade to detonate at three or four feet off of the ground, which amongst enemy troops would be most lethal. A hand grenade, effectively placed will kill five or six enemy. My experience was that grenades were used to keep the head of the enemy down to allow friendly movement if no M60 was available,or to take out foxhole or bunker personnel. If you are on the run, they are great for slowing down pursuers. They are also good for breaking things in general such as disabling an enemy vehicle. Placing a grenade under an ammo can full of rocks with the pin out and the spoon down was an effective booby-trap. If you tied a grenade to a tree and pulled the pin almost all the way out, then tied a string to the pin across a trail, that was like a mini claymore.

[Crash]

A breakable safety pin would be too unreliable, and dangerous. It would be better to make the safety pin strong, and have it spring loaded, functioning like a sear it would be held under the firing pin by a flammable string, that burns away when the propellant is ignited, opening the action. I'm picturing a few small bits of aluminum or brass available in sheets at hobby shops and the spring from a retractable pen.

It may also be possible to tie a big complicated knot in a string, that is tied to the firing pin and set in bondo with the top of the knot exposed to the propellant,perhaps seperated by a peice of a plastic bag or NC plastic. The String could then be soaked in a fuel/oxidiser mix that burns quickly when confined. When the fuse burns off the firing pin is let free.

This is much more compact than my other idea and could prove reliable, especially if you have access to safety fuse.

If your firing system is electrical then 2 inertial switches could be used facing opposite directions. The sudden acceleration of the round trips the one facing forwards which triggers a relay, arming the other switch.

Or you could just drill a tiny hole through the firing pin and stick a paper clip through it, then remove it before you put it in the gun. :wink:

[NightStalker]

Your post could have used a few paragraph breaks to make it more readable.

Just a little advice. :)

[Dave the Rave]

Man, The RPG7 uses an breackable pin, that can be removed prior to fire or let to break as soon as the rocket impacts on the target. As I say, this pin isn´t the main safety, is an plus. The main safety is the inertial pin and the secondary is the "rest against" pin.

I personaly think that stick an fuse throug the firing pin and hope that it burns out to free the pin is trust so much in God. You can´t relly on fuses that cam be damp, or burn too quickly or can be accidentaly cut to initiate the grenade.

Now, to the serious posters.

JC, the idea of delayed explosion on a secondary layer is very good ! We can adapt an simply timer to the warhead to initiate the system. Your idea of the coil can be ideal.

About the ammo, as far as I know, the common 40mm (250 grams) can be thrown about 500 meter, with the propelant of the shell. My idea is use an common 12ga (30 grams of doubllebased) to shot 400 grams of explosive, the same 500 meters. As I don´t know the formula, maybe Nbk can provide us with some useful info.

The barrel: At my country we have the 1 in. fence pipe. It´s an reinforced seamless steel pipe the same diameter as the 40mm barrel, and it can easily handle the 12ga pressure buildup. I think that is the most commom pipe, sold all over the world, but I will research and post about it.

Hehehe ! Tirany, as the form of government... As does Nbk and Mega ! It´s an reference to Montesquieu who said that the people can only be free when governed by an Tiran, who takes from them the responsability to decide from themselves. Those who don´t make decisions can´t be charged for it...

- Mods, sorry about my image stretcheing the layout of the forum, at my monitor it was ok. It will not happen again ! -

[MP5Guy]

Dave The Rave good luck loading that 1" Seamless Stainless Fence Pipe, better get out the lathe and turn that sucker just a bit. 26mm is roughly 1" so your better cancel the 1" and order some 1 1/2"which is roughly 39mm... :eek:
40mm Pom Pom Gun Barrel
http://www.hunt101.com/img/100277.jpg

[Dave the Rave]

Yep, but I am from Brazil and thing here are not like the rest of the world... I was thinking on the 1 1/2in. which haves (at my Country) 40mm dia, but I mistype and write only the "1"... hehehee !!!

Anyway, point taken and I will revise my posts for now on.

Nice junkyard, it´s all your ? Man, the things I could do with all those metal parts and tools... I even think of start datin a girl I´ve meet, just because her dad owns a HUGE junkyard...

[Baughb]

Dave, your idea seems a bit...clunky...at best, IMO. You're creating an entirely new ammo, really, and fitting it to a 40mm launcher. It seems kind of backwards, honestly. Plus, your ammo idea is pretty complicated. I've got to wonder how easy it'd be to produce quickly.

Also, there's the barrel detector on in your plans, a bit of the projectile that actually makes contact with the barrel all of the way out. That just seems like a very bad idea. If you're going to go with a rifled barrel, why not use the centrifugal force to do the work for you? I posted a while ago with a rough idea of how it'd work. It'd be small, easily adapted to a shell that would fit inside of a 40mm casing.

After all, isn't that what the improv. weapons forum is all about? If it ever came down to fighting with the Man, being able to produce effective weapons (and still be able to use whatever can be salvaged from your enemies?). That may not be 100% of the goal, but I think it's a thought on all of our minds.

(BTW, Dave: Tyranny)

[Dave the Rave]

Look Baugbh, The idea is make an 40mm from scratch, did you realize how hard could be to rifle an 40mm barrel ?

When you use my design, you won´t have to take out the prevoius spent shel, just to put a new round inside the barrel. About the "rest against" system, isn´t hard and ads a safety to an improvised weapon. By the way, all mortars uses the idea and it was working for decades.

Your idea was nice, but it will take some of the payload out to make room to batery and all those spprings and contacts. On the other hand, my project will give an bigger payload, with an simplier detonator.

Another thing that I like on my design is that, with the inertial safety and the "potato masher" detonator, the round can be used without the need of the launcher. You only need to hit the bottom of the round agains something hard do loose the inertial pin, then the safety will pop out and the detonator can initiate the explosive as soon as the round lands, thrown by your own hands.

BTW, thank for your copydesk, but, as you are not an Tyrant, I will mantain my signature as shown.

[MP5Guy]

And that Fence Pipe must be made of Kryptonite as 30 Grams of "Double Base" works out to 462 Grains pushing a 6160 Grain Projectile (400 Grams). A pretty Healty Dose for even Ord Steel With 1/2" Wall let alone Fence Post Stock. It is gonna Fuckin Blow Up In The Tube Dave.

You're Gonna Put Your Eye Out :(

MP

[Dave the Rave]

Good point Mp5guy, probably my calcs about the weight of the propelent are wrong... I will find it out and post again. But I think that the pipe can hold the pressure, cause it will build up slowly, and the chamber that will be pressurized will increase it´s size as the mortar moves forward.

- Mp5guy, You´re rigth, when I search my files I found that the weigth of 30 grams was about the whole cartridge, with lead shots, wad and powder. But there is nothing about the weigth of the propelent only. What do you think about the ideal propeling charge ? -

[JoeJablomy]

US 40mm LV rounds use .33g of M9 smokeless. 40mm HV use 4.2g-4.64g (M2 propellant). Bear in mind that this is with a high pressure chamber, and we still don't know precisely what kind of smokeless it is, because there could be any number of "M9" and "M2" propellants.
See TM 43-0001-28 for the cartridge data.
See http://stinet.dtic.mil/str/dodiss4_fields.html for mil specs, which may include the propellants in question.
Overall, your best bet is probably to use the propellant masses I gave as a general starting point and experiment.

[Grenade man]

Hello, I'm new here. Nbk200 your pic of the nylon case cutaway don't work for me, can you send it by e-mail or I don't know at steelrain89@hotmail.com and if you or anybody in this site know where can I find some real not nylon 40mm cases like m169, m118 or m918 or something like this, just email me please!! or just reply but I prefer e-mail please, thanks a lot you all seem to be nice people!

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

When asking someone to help you, or give you something, it's generally considered a good idea to SPELL THEIR NAME RIGHT! :rolleyes:

It shows that you're not some greedy grasping n00b who's too wrapped up in himself to pay attention to little details like MANNERS. ;)

NBK

[JoeJablomy]

Nylon cases can be bought on ebay by the dozen, and metal cases are less common and more expensive but are still an everyday item. 10 linked HV cases sell for about $10; LV cases seem to be a bit more expensive; possibly $5 ea. The easiest way to find them is to search for "40mm" and look under 'militaria' in the results.
BTW, grenade man, do you plan to reload them? How? Are there specific drawbacks to nylon cases for reloading with improvised projectiles?