Making barrels

[Jacks Complete]

I've run a search or three, but haven't found anything on making barrels. Plenty on trying to rifle the barrels, but nothing on techniques for making the blank yourself.

If this seems odd, it is probably because either I missed them on the search (it comes back with a *lot* of results!), or because the US members just go and buy a barrel blank.

I'm not thinking of making really high precision barrels, and would prefer to avoid the use of a lathe. Everyone keeps saying "Just buy some DOM tubing" but I can't find anywhere that isn't a barrel maker that sells it (or even lists it as stock), so why not make it at home?

In essence, I am thinking of some form of hot drawing process. Using either a charcoal or gas forge, heat the target steel rod to cherry red, doing it slowly so that the interior gets very hot as well, then dropping it over the tyre hole on your anvil and driving a hot punch through it. Start with a narrow one, and get a small hole all the way through. This will make further operations with heating a lot easier. Now heat it again, and drive the next size through, until you finally drive the size you want right through. If you think you can do it, you could drive a chamber too, but you would probably need to drive that before the final sizeing of the bore.

Does anyone have experiance with hot forging? Would this be possible? I think the contraction of the bore/barrel would have to be taken into account once cooled, and you probably couldn't get very long barrels like this. Could this be done accurately?

Even with a too small hole down the center, the metal would be easier to drill or lathe, since there would be a lot less metal to remove.

This would allow the production of stainless steel barrels, perhaps. It would even be possible to use a (an electric) forge to smelt the steel and cast a proto-barrel first, with a small central channel. This could be removed while still at the dull red stage (to avoid a liquid center), and driven through with the punches. Or perhaps drilled with HSS bits.

As for hot button rifleing, is it possible?

Anyway, this has gotten rather long for a speculative post. Depending on if there is any feedback that thinks this may be possible, I will likely give it a go on a dry weekend. Obviously, I'll only be casting and forging strong tubes, rather than barrels!

[SweNMFan]

Hmm

http://www.xtremeaccuracy.com/Rifle_Barrel.htm

Barrel-Making Technologies

Now that we've established certain basic terminology, let's take a look at
the various ways that custom barrels are made.

Single-Point Hook-Cut Rifling. This is perhaps the oldest extant technology used to create a rifled bore. First developed in the 15th century armament shops surrounding Milan, Italy, this most basic form of cut-rifling remains very much an artisan's craft. Indeed, with the exception of CNC controls, a journeyman barrel maker working for Beretta in the early 1600s would find much in today's cut-rifling shop quite familiar.

With single-point cut rifling, the craftsman selects a length of round steel bar stock, usually about 1.25 inch in diameter, for deep-hole drilling.
This operation, together with the reaming operation that follows, is as
important to the overall quality of the barrel as the rifling itself. In
this case, the hole is drilled and reamed to a size that is slightly tighter
than the land diameter for that caliber. Here's a brief but important
aside: Regardless of the rifling technique used, better barrel makers
typically will run a light abrasive lap through the bore to eliminate any
residual reamer marks. If a barrel maker says that he doesn't lap his
barrels, and you choose to use such a barrel, you should prepare yourself in advance for some fairly rough sledding in terms of bore fouling and
subsequent cleaning steps. Some barrel makers still insist that lapping
doesn't matter, but the facts are that it matters quite a lot. Caveat
emptor.

Once the steel barrel blank is ready, it is rifled. With single-point cut
rifling, a hook-like cutter literally carves out each groove, one at a time.
Generally, it can take as many as 20-30 passes of the cutter to finish just
one groove. Once the rifling is complete, the barrel is contoured to the
customer's specification and then lapped to improve the smoothness of the bore.

Very time and labor intensive, single-point cut-rifled barrels are typically
more expensive to purchase than any other barrel type, and given the
production limits of the process itself, high-volume production by a single rifling machine is all but impossible. Among its clique of devotees,
single-point cut-rifled barrels are considered the Rolls Royce of custom
rifle barrels. Today, the major U.S. suppliers of high quality,
hand-lapped, cut-rifled barrels include BlackStar in Texas, K&P in New
Mexico, Chanlynn in Colorado and Krieger and Obermeyer in Wisconsin.

Multi-Point Broach-Cut Rifling. This rifling process has much in common
with the single-point process, but represents an attempt to speed up the
rifling process by carving out all of the desired number of grooves at once. With two exceptions, today's broach-cut barrels are not made to the same quality levels as barrels produced by single-point cut rifling or button rifling. Today, manufacturers of black powder muzzle-loading rifles use much of the annual broach-cut barrel production.

After the steel barrel blank is drilled and reamed, a series of ever- larger broaches are passed down the bore, cutting all of the grooves deeper and deeper. Once the final groove dimension is established, the barrel is contoured to fit the customer's needs and either lapped or shipped to the customer as a completed piece.

Prior to Germany's development of hammer-forged barrel technology in the late 1930s and the American creation of button rifling in the 1950s,
broach-cut rifling was considered the high-volume barrel production
technology. Most of the military barrels made for turn-of-the-century
service rifles were broach-cut, as well as the wartime barrel production for the M1 Garand. In an attempt to further increase barrel production during World War II, military contractors began using broaches with only two cutters, producing the now-famous "two groove" barrel for the M1 rifle.

Today, the major U.S. makers of high-quality broach-cut barrels are Olympic Arms in Washington State, and Badger Barrels in Wisconsin. At the time of this writing, neither maker laps its barrels.

Precision Button Rifling. During the 1950s, Remington Arms engineer Mike Walker began experimenting with a new rifling technology that would eventually become the dominant production technique for high-quality custom rifle barrels. Called "button rifling," the new technology effectively bridged the gap between the quality problems associated with high-volume hammer forging and the production problems associated low-volume, high-quality cut rifling.

Steel barrel blanks destined for button rifling must start out the same way as their single-point cut and broach-cut cousins. The blank is deep-hole drilled and reamed, usually with rebuilt, early 20th century Pratt & Whitney drilling machines. As discussed above, some makers like to run a light lap through the bore prior to rifling, and others don't.

Made from very hard carbide, the "button" in button rifling has been
carefully machined with the reverse of the rifling pattern that is desired
for the barrel. It is marginally larger than the hole in the barrel blank.
This button is pushed through the hole under great pressure, displacing the steel into lands and grooves. In many respects, the process extrudes the rifling into the barrel, with the button acting as a moving, mini-mandrel.

As you might imagine, this process can put a lot of stress into the barrel
steel. If a button-rifled blank is contoured without any prior stress
relief, the release of the radial stresses resulting from the machining
process will cause the bore dimension to grow radically and unevenly down the bore. Button-rifled barrel makers most often eliminate these
dimensional variations by lapping the bore after contouring until the
dimensions are uniform and the surface is smooth. Some, including
BlackStar, Pac-Nor and Krieger, apply cryogenic stress relief technology to their barrels to completely eliminate stresses. In addition to being the pioneer in integrating cryogenic tempering into barrel production, BlackStar is the only barrel maker to apply this important technology twice to every barrel that it makes.

Today, most of the barrels used in benchrest competition are button-rifled, proving that these barrels are capable of producing consistently high levels of accuracy. The top custom button-rifled barrel makers in the United States include Hart Barrels in New York, BlackStar and Shilen in Texas, Lilja Precision Rifle Barrels in Montana, Pac-Nor Barreling in Oregon, and Schneider Custom Barrels in Arizona. Douglas, the old barrel maker in West Virginia, dominates the U.S. production of less expensive, after-market barrels.

Hammer-Forged Factory Barrels. First developed in Germany, hammer-forging technology is a method of manufacturing a large volume of barrels very quickly. Today, this technology dominates factory barrel production and is in use by Remington, U.S. Repeating Arms, Sturm Ruger, and many others.

In hammer forging, a short piece of barrel steel is extruded along a mandrel that has the reverse of the rifling form desired for the barrel. Unlike button rifling, however, hammer forging forms the barrels around the mandrel, rather than putting rifling into a full-length piece of bar stock. Despite all of the marketing hype, however, hammer-forged barrels are rarely paragons of accuracy and performance. Laden with internal stresses, these barrels also often exhibit very rough bores, which are the result of poorly maintained production mandrels. All in all, most gunsmiths do not consider hammer-forged barrels to be good candidates for a high-quality custom rifle.

Barrel Steels

Today, you have two basic choices in barrel steel: traditional blued chrome moly steel and the more modern stainless steel. During past years, partisans for both have made a wide range of claims about their respective qualities and advantages, most of which had little basis in fact. Today, stainless is by far the most popular steel in the custom barrel category, and it is on the rise in factory barrels as well.

Obviously, blued steel delivers the more traditional look to a rifle, and
many, many shooters still prefer the old-style aesthetic to the modern, racy appearance of stainless actions and barrels. I definitely fall into this category when the subject turns to high-grade, Circassian walnut-stocked hunting guns with express sights or low-power scopes. After having done the synthetic stocked, high-performance stainless rifle bit, I have returned to the warm feel of great wood, the subdued colors of fine bluing, and cartridges that are about more than just raw, pedal-to-the-metal velocity. However, I also don't take these rifles to wet, humid places, nor do I use them in competition.

With this last two considerations uppermost in our minds, we come the place where stainless is king. If you are a benchrest or high power competitor, a stainless barrel is the way to go. Generally, the primo accuracy life of a conventional 416R stainless barrel will be a bit longer that blued chrome moly. If you hunt in soggy or salty conditions, you simply have no choice -- a synthetic stocked, stainless rifle is the only way to go. While 416R stainless is an improvement over blued steel, a new 17-4 type stainless barrel steel developed by Crucible Steel and BlackStar is by far the most corrosion resistant on the market. It is called SS700, and it is more corrosion resistant and erosion resistant than any other barrel steel currently in use. After two years on the market, barrels made from SS700 have consistently demonstrated a 3X-4X extension in throat life and commensurate top-drawer accuracy.

I own several rifles with stainless barrels, and they are really super at
resisting the effects of southeast Texas' high humidity. If you object to a silver rifle on the grounds that you hate the way it looks, there are a
number of cosmetic fixes that will also boost the corrosion resistance of
the metal even further. The first is Black Teflon coating, which is often
marketed under the trade name "Black T." A stainless rifle treated with
Black T will acquire a very nice black satin appearance that most
traditionalists find a great improvement over bead-blasted matte stainless. This is available through many vendors across the country. An important detail about Black T: make sure that the person doing the work applies a mil-spec phosphate primer to the metal work prior to using the Black Teflon. The second option is Black Titanium Nitride, which is a matte black, completely indestructible surface treatment available through Ultra Light Arms of West Virginia. This treatment is available on barreled receivers and other gun parts, but not the bolt body or bolt handle. Both options are excellent, with the nod going to Black T for aesthetics and to Black TiN for utter durability.

[Jacks Complete]

SweNMFan,
I'm well aware of how commercial shops button broach their barrels - we have had many discussions here about the in's and out's of trying to rifle a barrel. The basic consensus is that for the home shop, you are highly unlikely to be able to do it, since you need a set of custom made carbide cutters and a huge hydraulic ram to push it. It also assumes that you HAVE A BARREL TO START WITH!

The whole point of this thread is to make the barrel, as opposed to buying a tube. This is about hammer forgeing your own. Your post is almost completely unrelated to that. It offers nothing at all that is useful, aside from the two short paragraphs in the middle.

Hammer-Forged Factory Barrels. First developed in Germany, hammer-forging technology is a method of manufacturing a large volume of barrels very quickly. Today, this technology dominates factory barrel production and is in use by Remington, U.S. Repeating Arms, Sturm Ruger, and many others.

In hammer forging, a short piece of barrel steel is extruded along a mandrel that has the reverse of the rifling form desired for the barrel. Unlike button rifling, however, hammer forging forms the barrels around the mandrel, rather than putting rifling into a full-length piece of bar stock. Despite all of the marketing hype, however, hammer-forged barrels are rarely paragons of accuracy and performance. Laden with internal stresses, these barrels also often exhibit very rough bores, which are the result of poorly maintained production mandrels. All in all, most gunsmiths do not consider hammer-forged barrels to be good candidates for a high-quality custom rifle. Yet even this is mostly irrelevant, since it tells us nothing about the process. I am not talking about hammering the steel around a mandrel (which requires immense forces and huge machines), but of punching through the hot steel to form the barrel. The steel would be fully stress relieved, since it is being worked hot.

This is a new production idea that takes into account the abilities and needs of the home workshop and the users of this forum.

It isn't just some article copied and pasted from the web.

[SweNMFan]

I wouldn't use a homemade extruded tube atleast.. (maybe for .22LR)


With single-point cut rifling, the craftsman selects a length of round steel bar stock, usually about 1.25 inch in diameter, for deep-hole drilling.

If it was good at the 15th century guess it's still good.. I would drill it, as for me that seems the only way to be sure that the material have the same strenght all the way.

Anyhow found a article on the subject..

[knowledgehungry]

Drilling really sounds like your best option, it will take a long fucking time to get through it, and you will probably go through a lot of bits but tempering your own steel isn't easy and I wouldn't trust it. Also pounding a straight hole through something seems hard, you've got to have a real steady hand unless you have a different way of hammering it.

[akinrog]

Sir,
if you hot or cold forge steel stock to create your barrel blank, you will not only worry about contraction and changing barrel bore size. Since you have to do it manually there shall be very different densities, hardnesses, and residual stress. So I am not certain if it is feasible (but who knows human beings are capable dwellings, one may perfect the techniques you described, given the fact that the people make tree log cannons to shot cannon balls in case of necessity :)).

As for the hammer rifling they use reciprocal hammers to create rifling on the blank. However in this case it is again barrel blank not steel stock. It is a little bit (???) oversized though (however, no hot processes are mentioned). And I read somewhere that there is residual radial stresses which are hard to eliminate. But the (rifled) barrels produced in this manner are very wear resistant (which are used for fast machine guns).

Here is a link for barrels and rifling (http://www.border-barrels.com/articles/bmart.htm)

In a thread I suggested manually hammer rifling the barrels but the members disproved its feasibility since it is really very hard (if you assume manual method). However, maybe a hybrid method (hot hammering) may be a way to go. Assume that you have a heavy steel tube (according to link above stainless steel cannot be hammer rifled due to hardening problem), drilled by a machinist and you have also a negatively rifled (meaning there are groves instead of lands and lands instead of grooves) rod which also has a section for chambering (again according to the link the sophisticated hammer rifling machines (aka rotary forging machines) can spit out a rifled and chambered barrel every three minutes.), one may produce a rifled barrel. However it is really problematic since, say you have a steel tube having a wall thickness of 1,5 cm and a bore of 10 mm (in order to fool the machinist), it shall be really problematic to forge it in a one go.

[Jacks Complete]

It doesn't take long, nor much force, to drive a spike through a piece of hot steel. It is about the consistence of cold butter. When hot enough, (most) steel loses all of it's strength, and, indeed, will melt into a thick tar like liquid unable to support it's own weight. All stresses are removed by this process, which is very very different from the type of cold hammer forging barrel makers use these days for mass production.

You can make the walls as thick as you want, use any type of steel you want, and you can temper it how you want. For something as wimpy as a pistol cartridge, I can't see any chance it could go wrong if you use a good bar and good thick walls.

As for getting straight walls, through the middle, etc. that's why I was asking if anyone had any experiance doing similar things. I know it is quite easy to "drill" a hole through an inch of stock from the side (it is the standard way to make a rivet hole, for example) but I don't know of anyone who has tried it lengthways, since there are no reasons to do it, except for making a barrel or the like.

I can see that using something like a jig might be a good idea, and, unfortunately, it would be easiest to make the punches (or the final punch) to the exact dimension in a lathe, but a file and a bar clamped into a drill should do at a push.

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is kind of the shape you need. The point pushes through, then opens up to the size you want, then tapers down to avoid drawing the heat too fast, or getting stuck. Once through, the tool drops right the way through. It should be a little longer than the barrel, but go long, as the steel will stretch a bit as you drive.

Note that this is all still theory. It would probably be easiest to build a jig, then push the tool through the steel with a hydraulic ram. See attached.

Note that the jack in the picture is fully extended in the last step, but hs yet to get through, since I made the initial bar slightly too long. In the next step, the punch would have dropped free from the ram, as it isn't actually held in place vertically, but sits inside a tube attached to the ram. This way, the bore would probably be quite consistent. The one shown would be good for black powder, as the end would still be closed, and all it would need is a flash hole drilled (assuming the punch could be removed!)

[tdog49]

Jack,

I can see nothing wrong with your ideas, really this is basically ( one of the ways) how blackpowder rifle barrels are made. .45 acp is a smokeless version of the .45 colt and as such tops out at just under 18,000 psi (17,700 being a hot load according to Hogdon) w/ the .45 colt running at 13-14,000 psi. should be easily handled by cold rolled steel with a 1/4" wall thickness.

9mm however runs between 27,000 and 32,000 psi , so heat treating becomes much more critical.

I do think that drilling would be better than punching but that is just my opinion. Definitely better for stainless. Punching stainless might make the hardness go off the scale. In my welding, I've had stainless end up in the 300-400 range. because of exccessive heat.

not good.
anyway, good luck.

[john_smith]

No experience with forging (or barrel making in general), but I'm surprised noone has brought up the Hoffman gunsmithing books yet...lots of info about drilling blanks here.

[Dave the Rave]

Mostly because Hoffman doesn´t spoke about neither hot hammering nor hot drilling if we can name it that way.

I believe that JC´s idea sounds very feassible and could be done with an small hydraulic hammer, but only some workshops have one... Another thing, we may need to use some kind of outside casing, or else the drill bit could be driven transversally to the axis of the blank or cause some irregular deformation on the blank.

Anyway, both hammering and drilling could be done with the same hydraulic hammer, but hammering will need an internal pattern and an pre - drilled blank, so we again fall into the option of hot drilling.

The sketch JC´s provided looks like some extemdable mandrels I´ve seen on some sites. I´ll do an search and update this post with all the links I found.

[Jacks Complete]

Dave, the idea with this is that the jack pushes through the hot steel, rather than a hammering action. Hammering would probably work, though.

The idea of having the tool able to rotate is that you could, perhaps, use a wrench to twist the tool as it went down, in a controlled fashion.

You are probably right about using some kind of guide. I think it might be poosible to use a square section bar, as this would be very easy to avoid turning, by a clamp or something down one of the flats.

I got some 1" steel bar from the scrapyard today, round section, so I will give it a go if it ever stops pissing with rain! Forging in a high wind isn't fun either...

[Anthony]

You can get nice steel tube, I was looking in the engineering workshop at work the other day - approx 10mm bore and similar wall thickness. Can't remember if it was seamless, think it might have been. But even welded would probably do?

This may sound obvious, but have you tried a big metal supplier like Corrus? They mostly deal with trade accounts, but if you speak to the right people they should be able to sort you out some off-cuts for cash. This stuff must come from somewhere!

More conventionally, RS do hydraulic steel tubing (must be seamless!) There are minimum quanities, but in the small sizes the price still isn't too bad. From memory, the 6mm ID size has a bursting pressure of ~60Kpsi

I will be very interested in the results of your hot "drilling", and will be very impressed if you can produce a foot of barrel with a a straght bore! The best I ever got was a deviation of about 2-3mm in a ~50mm length, with a cordless drill :)

[Dave the Rave]

JC, from I could find, the hydraulic hammer can also be set to push, and the anvil of the machine can hold the square tub so it does not turn.

About the mandrell, I found an reference on an machinist book, but I can´t scan right now, so I´ll look for it on the net. the mandrell uses its on guiding rods to rotate, so its no necessary to use an external tool.

Good luck on your forging and I´ll search for references, as we need to discuss the rifling ideas to the hot drilled barrel.

[akinrog]

Almost a year ago, I watched on discovery a documentary related to guns of 1800. It stated that during that time there were gunsmiths in military service to repair guns. Since there is no standard guns (all guns are unique since they are hand made), the parts are not interchangable and a gunsmith is needed to repair guns.

Anyway the point is the documentary showed how guns are made during that time. The gunsmith was rolling a hot and thich steel (iron?) plate around a round steel bar and fusing the edges rolled around the steel rod by hammering it hot. The flintlock (its ancestors?) is said to be produced in this fashion. So I don't think hot forging or drilling is a bad procedure. But as many experienced members stated the ammunition of that time was weaker than today's ammunition and it might be dangerous to use such a barrel with modern ammo.

Only testing it may reveal its value and reliability. But something tingles in my mind. How one may keep the hot stock to be drilled/forged steady? I mean since you drive the tool into it to create the bore, it might bend, tilt or move defeating the procedure.

[Dave the Rave]

Akinrog, that´s almost the same way they do the hammer forging, but the internal rod has grooves to make the rifling. Of couse, the hot blanks isn´t an plain sheet of steel, but instead it´s an seamless tube, sligth shorter and larger tha the final barrel, so when hammered it goes longer and adjusts itself to the diameter of the final barrel.

I believe that to weaker charges or to black powder guns the plain sheet method works well, but to larger, stronger charges, it´s necessary to use the hot drilling method.

As we spoke about short barrels, it´s easy to work only with teh hot drilling which is less time consuming and gives an better final product.

I´m about to get fired again, so I can´t search more on the web, I beg the pardon of my forumates, but I´ll have to give a break on my searchings. ASAP I´ll be back and post what I can found.

Regards.

[akinrog]

A theoretical thing came to my mind. What about casting that slightly larger barrel blank everybody (including me) referred to above?

After casting it, it is feasible to apply hot hammer rifling method?

And anybody knows how drilling was made before barrel drilling machine is invented? I mean during early and (maybe late) 1800s, the modern barrel drilling machines were not present. And gunsmiths of that times were using a (maybe more rudimentary) method to drill barrel bores.

[Jacks Complete]

Dave, hot hammering is not easy. Well, ok, it is easy, but not to do well! Getting a good weld all the way along and round without overly thinning the metal would be hard. Also, I would *really* not trust something that someone at my skill level did, unless it started from a good piece of seamless tube - but if I had seamless tube, why would I risk wrecking it to hammer it? I could just make the ammo to fit, since that is far easier (see the "case blowing/fire forming cartridge cases" thread)

The whole point of this idea is to NOT have to buy seamless tubeing from somewhere first.

I could, if I wanted, build a rifleing machine, and an extension to house it and the lathe. However, I am looking to get a very much simpler process going.

The picture shows a press, not a hammer. The idea is to push through while the core of the metal is still soft as butter. The bottom end is gripped, and the form is pushed by a ram right the way through. It *may* be possible to form a rifled barrel by carefully twisting this form as it gets pushed through.

akinrog, if I were going to do that, I think it would be easier to simply cast a barrel around a rifled barrel form. However, getting the pour just right on the steel would be hard, and I would be loathe to trust it. It would probably be quite different to what you melted in the first place by the time you poured it, and it might wind up as brittle as cast iron. Which would be bad! However, by getting a good bit of steel and taking that up to a high temperature, only the outside will be destroyed by heat, firescale, etc. and the majority of the bar will still be good quality high strength steel.

Before the 1800's, barrels tend to have been either carefully drilled (just lower quality than more modern barrels) or simply cast. Some were hot hammered around a mandrel, and the metal was called Damascus, wherein two different steels were hammer welded together around the form. Damascus barrels, when done really well, are as strong as a modern barrel. However, it is impossible to tell if they are perfectly welded all over, and so they are only used for shotguns. Only a few talented smiths make knifes or barrels this way today. The earliest guns and cannons were cast, and I have seen documentary evidence of how they failed! However, they didn't often have rifleing back then, and nor did they understand the use of "chills" in casting.

EDIT: Wow, that was lucky! I got a "server too busy" message three times, and thought I had lost the above... Just kicked it through 15 hours later!

[akinrog]

While searching about damascus steel, I came across the following book cover which (I believe) means making cannons in damascus (I cannot speak French but I guess it is so).
Anybody can reach to this book.

http://damascus.free.fr/f_damas/f_hist/i_liege/liege.jpg The site has interesting information about damascus and wootz steels, which renders it very valuable.

Edit Forgot to add actual URL (http://damascus.free.fr/f_damas/damas.htm)

Although off-topic this link (http://damascus.free.fr/f_damas/f_hist/perret.htm) from the site gives info how damascus steel is made in 1700s. I hope the information given is inspiring.

Edit: While searching through over the net, I found another article related to RSP (Rapidliy Solidified Powder) metalurgical method. WHile RSP is somewhat complicated for an amateur, the article gives hints how barrels are made during old times. I cannot help quoting a part from the article regarding ancient method of making barrels (especially the part about damascene barrels are very striking).

"Firearms were developed in the 1500s but over time, weapon smiths had problems making gun barrels capable of withstanding increasing gunpowder loads: The original longitudinal forgeweld down the barrel length was a weak link," says Billgren. During the 1700s damascene barrels developed in Turkey were forge welded as a spiral. The spiral weld increased the strength in the transverse direction. The Damascus was made of soft iron and hardenable carburized steel. "The result was a primitive toughhardening steel with a middle carbon content in the range of modern gun barrel steels. The spiral welding turned the forging grain in a favorable direction and the resulting damascene pattern again served as a quality certificate setting the damascene barrels apart and making them the barrel of choice throughout the 1800s," says Billgren.


Spiral forge welding maybe an option for creating barrels. However this process I think requires delicate forging skills.

Edit : I also forgot to add URL (http://www.machinedesign.com/ASP/viewSelectedArticle.asp?strArticleId=57611&strSite=MDSite&catId=0) of this quote

[Jacks Complete]

Yup, making a Damascus barrel is like making a chain - it might look solid, but it is as strong as the weakest weld! The issue is that you need to be really, really sure you are getting a good forge weld all the way, or else it will fail, and kill or maim you.

You need to know your fluxes and your steels, as well as be able to forge weld well before even trying.

[akinrog]

When I review the last link I gave, I saw an image (at the right) which describes evolution of barrel making.

According to this image, I had the impression that the latest gun barrel making technology involves swirling of the hot (molten??) barrel while drilling it. This makes the grains traverse.

I hope this does not sound kewlish. But how about using a really strong plastic for disposable barrels. AFAIK, UHMWPE (Ultra High Molecular Weight Polyethylene - aka the material which Spectra Armor Plates are made) is used for armoring vehicles and bulletproof vests. This plastic is very though but thermoplastic (which renders it useless for reusable barrel, but I believe it may withstand a few shots).

This type of barrel may be a candidate for disposable assassination weapons.
How about this idea?

[Jacks Complete]

Not bad. Make a laminate barrel, too, with something like a fibre-wrapped thin walled tube.

Tree trunks work quite well.

Heck, there is even the "cardboard disposable shotgun".

Just use a low load in the cartridge (if you bother with one) and make it single shot with several barrels. You could probably cast one out of a tough thermoplastic, so you had a pepperpot type of affair. It would probably pass inspection more easily like that, since it wouldn't be metal, wouldn't look like a barrel, and could, in fact, look like a toy.


As far as I know, the latest technology is to hammer the metal cold, so it workhardens, and this produces good cheap barels. Hot hammering was used before the lathe became a big thing, a long time ago.

[prespec]

Hardness is not a requirement in a barrel, 28 Rockwell C is adequate, 32 is better. Toughness and ductility are useful attributes, abrasion resistance too.
Most ordnance steels fulfil these requirements......416RBS stainless, 4140, and many others.

Ductilty is useful to achieve a smooth finish, toughness to resist 45-55,000 psi pressures at the chamber and abrasion resistance to mitigate throat erosion from propellant gasses.

Hammer forgeing is a popular commercial method, but set-up costs are high.
These barrels will often exhibit a wash-board effect internally, which has no apparent effect on accuracy.

Button rifling is the method of choice for match barrels, and most benchrest shooters will use these. It offers uniformity of twist rate and is better suited to the requirements of custom barrel makers. Tooling is still quite sophisticated an in general, pull-buttoning gives a better result than push buttoning.

Cut or broached rifling can be done with fairly basic gear and is probably the oldest method. Many passes with a light cut will do it just fine , but twist-rate variations are common.

All of these can produce a tack-driver, when done well.

Many long-rifle barrels were made in two longitudinal halves, which had been chiseled to form a lengthwise groove, fire-welded (forged) together, than susequently drilled, reamed, then cut-rifled.
These were subjected to pressures around 12.000 psi , and were more than adequate , but would fail under the pressure modern smokeless cartridges generate.

I would like to continue this discussion, provided I don't get banned as a presumptious newbie. I may have things to contribute, and really enjoy the site.
We shall see in a day or so.

[Jacks Complete]

Not been banned yet, as far as I can see. And that's a fairly good first post.

However, hardness *is* required. Not too hard, though. What you want is a very hard inner liner to the barrel, to protect the throat and bore from friction erosion from the passage of the bullet. If it was too thick, you would get cracking due to the thermal stresses. Beyond that, you want a high strength, tough barrel. Ideally, a crystalline barrel would be perfect, as long as you were sure it couldn't shatter, as the dimensionallity would never change.

I've not heard about two halves of a barrel being stuck long-ways. Got any references for that? You might be thinking of damacus-style barrels, which were formed from two forge weleded bits of steel, one hard and one ductile, to make a tough mixture, which was hot hammered and forge welded around a mandrel. This was used on old shotguns, but had a high failure rate, caused often by electrochemical erosion at the welded steel seams, some time down the line.

[prespec]

Hardness in steel is relative, ie., that which is suitable for wearing parts... 50-55c,....sears and the like, which is usually too hard for stressed parts like barrels. As the hardness increases , the brittleness asserts too, along with absolute tensile strength.
However, wear resistance to throat erosion from powder gasses and primer residue seems to be pretty well met by good ordnance steels in the low to mid 30's.

The passing of the rifling button seems to work-harden the surfaces to a degree too.
Some barrelmakers have used annealed 416 stainless, and this can go as low as near mild-steel. It makes a great looking tube , but will burn out quickly and, in a real high-pressure cartridge, the chamber can deform.

As to the longitudinal barrel technique, it is not a construct of my mind, and if you will give me a few days I shall find the reference material. I am well aware of the Damascus process and am not confusing the two.

These early barrels I am describing were made out of iron and , in the context of this discussion, the carbon content was negligable, and , as you are probably aware, wrought or forged iron has entirely different properties from steel, and cast iron.
It exhibits toughness and the ability to be joined by the hammer and anvil, to the point where it can be considered homogenous.
It also resists corrosion better than many modern steels. In fact the phrase "modern steel" is an oxymoron, as true steels were accidental in any significant quantity the Western world until the late 19th century.

I shall still find the reference book....even now it sits crated in my shed... having just moved. I think it is called ," A Guide to Blacksmithing" or similar and was published in the the 1950's.

BTW....I lost count of the barrels I have chambered, threaded, and fitted, somewhere in between 600 and 1000.

[Jacks Complete]

However, wear resistance to throat erosion from powder gasses and primer residue seems to be pretty well met by good ordnance steels in the low to mid 30's.Hmmm... If you consider 1000 rounds before accuracy drops off to be "pretty well", perhaps, but there is a reason why even shotguns have hard chrome liners these days, and it isn't just corrosion afterwards.

BTW....I lost count of the barrels I have chambered, threaded, and fitted, somewhere in between 600 and 1000.I could be a little sarcastic and suggest that if you use a slightly hard steel, you wouldn't have to keep re-chambering them! However, I'll stick a smiley on the end for you ;-)

That sort of number indicates you to be a gunsmith, or a very heavily involved US pro-am. There are full-time UK gunsmiths who won't have done that many in ten years of trading, if they have even done one in house, rather than shipping them off to a third party, or just bought them in as replacements.

I can tell you are going to be a useful person on the forum.

Please do find the longditudinal info, I'd be very interested.

[prespec]

Herewith link to the relevant pages from " The Art of Blacksmithing" , Alex W Bealer, 1976,1969, ISBN 0-7858-0395-5.

http://i109.photobucket.com/albums/n52/prespec/Rotationofbarrel2-1.jpg
http://i109.photobucket.com/albums/n52/prespec/Rotationofbarrel1-1.jpg





You will notice they differ in some particulars from the process I described, thus proving memory to be a frail thing, but is essentially the same.

I hope this is of use to you and if any difficulty is had with accessing these links, I can PM you a PDF file.

As to the hardness figures stated, these are typical of good stainless barrels, the annealed steels referred to barely making the C scale.
With properly loaded ammunition , in quite high-velocity chamberings, it would not be unreasonable to expect a useful barrel life of 3000-4000 rounds, possibly quite a bit less for extreme match accuracy, and high-intensity chamberings, and somewhat more for hunting requirements.
However, too much of the wrong powder can cause serious throat erosion after several hundred rounds. And more barrels are ruined by careless or total lack of cleaning, than by normal use.

BTW... I have noticed these pages appear to be of low quality, and I shall get up to speed with posting attachments on this forum after this weekend.

[Skean Dhu]

After reading your post and much pondering. I theorized one could could Draw a tube out over a mandrel after heating and then using a tap of sorts simply create the rifling grooves in the barrel.

There are also a number of patents that could prove to be useful in creating the effect you want.
US patent 5,438,858 creates a rod with internal helical bore holes
US patent 5,533,375 creates a seamless tube from hollow billets
and if you use the search functions on www.USPTO.gov and enter the following parameters
CCL/72/264, CCL/72/263, CCL/72/265, CCL/72/266, CCL/72/269, CCL/72/274, CCL/72/276, and/or CCL/72/286 you will find numerous patents dealing with the drawing of metals through various dies and over mandrels with different results. Surely one of the above will either allow duplication exactly or inspire the modification to suit your needs.

[Jacks Complete]

prespec, thanks for the scans. High enough quality for me to read every word!

I have seen the coiled form before, but never the single part welded around a mandrel. I might have to try that. The scarfed version would seem to be a good idea too, as it would take somewhat less skill to achieve a good result with that.

I'm not sure I trust my (forge) welding anything like enough to trust it to a barrel, but for a more experianced smith it would probably be an afternoons work.

[prespec]

Not a recommended technique for modern ammo with smokeless powder.
Even the mildest steel with a hole drilled and then reamed would be far safer, provided it was thick enough in the chamber area.
The process of crude rifling is described elsewhere on this forum, but it is easily enough done with some basic machine tools.

[wolfy9005]

If you could somehow make a ceramic "cylinder" which is capped at one end, and perfectly smooth you could make your own seamless tubing. It just involves the moving of the ceramic bit(or anything else that can withstand molten steel), and pouring it into the mold slowly until the desired thickness and length is aquired. I'll do a bit of research, and if i find time ill post my finding.

The barrel punch idea would work, but the "blank" would have to be kept hot for the whole time, then tempered/annealed(the strengthening one, i cant remember). To keep it hot your could use gas "jets", or maybe an oxy-acetylene torch. If you dont, the bottom will cool too quickly, and the whole process will stop. Do some tests with making 1",2",3",4" and 5" barrels from low quality steel(mild steel) to perfect the idea. Mild steel is cheap(ish) and has roughly the same properties(and density) as say, stainless steel.

Thats all for now.