Category Archives: Weapons Technology

Setting Up and Using a Ransom Rest

How to separate the pistol’s potential from the pistolero’s: the Ransom Rest and a grip insert that fits the firearm.

There are several ways to test fire a handgun, whether for function, for accuracy, or for any kind of instrumented testing, like chronograph load development or strain-gage pressure measurement. In ascending order, these are: by hand, from an improvised rest such as a sandbag, or from a machine rest.

The best commercially available machine rest is the Ransom Rest and it has been for a long time. It is, as you might expect, premium priced, and it also takes quite a bit of installing and setting up.

Steve Sieberts has an excellent article on setting up a Ransom Rest, one we wish we’d had the first time we monkeyed with one back in 1980 or so, in the American Handgunner online.

The Ransom Rest has been around since 1969, and really is the gold standard for gun/ammo testing.

I was building a new Caspian 1911 .45 ACP last month and needed to test it, and obtained a new Ransom Rest and insert for the 1911 from the fine folks at Brownell’s. Getting the most from a Ransom Rest means building a mounting board for it, that way it can be secured to the shooting bench at your local range. Most ranges have shooting pedestals made from cinder block with a concrete top. This is a very sturdy basis for attaching the mounting board with the Ransom Rest attached.

Siebert’s setup with a target 1911. Even the trigger contact is mechanical on a Ransom.

Note his mention of “insert for the 1911.” The Ransom Rest grips handguns in a sort of vise, and for that it must have custom jaws to fit the particular gun, in Ransom terms “inserts.” (Current ones are blue). This can be a considerable expense of its own, with the inserts costing $60-70 each now; but the bigger problem is that they are only available for the most popular sidearms. Especially for the ones popular when the Ransom Rest was introduced, like the 1911 and the S&W K-Frame!

(And no, this is not just sniveling because they don’t make an insert for the CZ-75 — they do. Like all the non-1911 non-Smith inserts, it’s a month or two special order, so you need to plan your Ransom Resting well in advance).

As for the price of the unit itself, well, that’s why they call it Ransom. The Ransom Rest, Windage Base and one set of inserts will hit you about $750 at Brownells, today. (You can save about $100 off that at Champions Choice, but we’ve ever dealt with them. They also seem to offer a different selection of inserts than Brownells). But it takes the major source of inconsistency — us humans, or as Small Dog Mk II thinks of us, Trained Feeder Monkeys — out of test firing.

The sine qua non of good results with the Rest is the setup. It has always come with good instructions, which now have a visual supplement in Siebert’s article.

Remember, you’re trying to remove as much movement as possible, in order to make sure the pistol returns to the exact same spot for each shot. If the bench you’re attaching the mounting board is wobbly, you’re just wasting your time.

via Building And Using A Ransom RestAmerican Handgunner | American Handgunner.

We don’t know how old Sieberts’s article is; for all we know, it’s as old as the Ransom itself, but really, it’s timeless.

For most target shooters, the stock inserts will cover you. For the rest of us, the insert problem actually looks like a perfect place for 3D printing and possibly, small-shop injection molding.

The biggest beef we have with the Ransom is that we’re not sure where ours is. Would be a drag to replace it (although that would guarantee finding the old one).  The next biggest? That there isn’t a rifle version. We haven’t found anything nearly as good for long guns.

Further Improved Gluty AP-9 3D-Printed Pistol

Back in July, most of the bugs were worked out of the Shuty MP-1 by its designer, Derwood. With some help from Warfairy, who customized a lower design for the project, Derwood had redone the upper, improving the ejector in the 9mm pistol that uses Glock magazines and barrels. Here’s the July video, again.

But it’s not in Derwood to rest on his laurels, so there’s a new version, which he’s calling the AP-9. No files yet (if you follow the link in the video above to YouTube, the links to the old files still lead to working files).

It appears that he made changes in the recoil system, primarily, and the stone-simple ambidextrous magazine release system has been reprinted in a lighter-colored material, possibly nylon. Presumably, this new version retains the improvements noted in last summer’s firearm, but adds further improvements.

The upper receiver is changed relatively little, externally, but is definitely a new print. Left side view:

The biggest change seems to be the replacement of the original recoil spring with an AR-like buffer and large diameter spring. This required an end-cap and buffer tube assembly (which could conceivably be a single print, or perhaps is a simple end cap threaded for a buffer tube) which is new to this variation.

Meanwhile, career bureaucrats and political-appointee holdovers at the Departments of State and Justice and the Bureau of Alcohol, Tobacco, Firearms and Explosives seem to have doubled down on their commitment to stop the signal. Lotsa luck with that.

What’s Happening in SF Arms Today

There are a number of things going on right now, some of which may be trends.

More and Heavier Weapons

When we joined SF, while there was plenty of access to weapons that were heavier/more specialized / foreign, what an ODA carried was 12 M16A1 rifles (if we were fortunate enough to have 12 guys and zero empty slots, which happened… let’s just say, rarely). Soon, they gave us two M203s so we didn’t have to keep bumming M79s that Big Green wanted to get rid of.

Since then, the trend has been to push more and heavier weapons down to team level, giving the team increasing mission-driven options.

Background

By the start of Afghanistan, we had SOPMOD I M4A1s, two of them w/203s per ODA, 7.62mm (M24) and 12.7mm (M82A1) sniper rifles, and had just gotten M249 SAWs. We borrowed everything else or bought it out of theater-specific money: AT weapons, a full suite of suppressors, etc. (Suppressors were part of SOPMOD I but ours got stuck in the pipeline and we got 2/team after deployment).

We had claymores and toe-poppers, and in 2003 had to turn them in because some drone in the foreign service had made an unwise promise to the ghost of the least consequential Briton in history, with the possible exception of Boy George, to wit, Princess Diana.

Demolitions have become more urban-centric lately. Your average SF demo man can rig a door to blow in two seconds flat, but send him into a forest to blow down trees for an abatis, and you’ll see him sneaking peeks at reference material.

With the evolution of the war, the weapons evolved rapidly with many more versions of precision rifle appearing, the Mk17 SCAR with several barrel lengths, and variants on the M4 / Mk18. We finally got M240s, M2HBs and Mk 19s of our own, rather than borrowed from Big Green. And bigger weapons yet began to ride our vehicles, notably M134 Miniguns and some SOF-specific weapons.

Where We Are Now

The basic weapon remains the M4A1 with several different uppers available.

Changes since Your Humble Blogger retired include free-floated rails systems, much better general issue 5.56 ammunition negating the need for Mk 262 77-grain, HK grenade launchers partly replacing the Mk 19 (the HK’s a much better weapon), and Mk 44 (currently Mod 3) replacing earlier iterations of Miniguns.

Pistols are a special purchase of the Glock 19, Gen 3, with the MOS slide and the Docter optic as previously used atop some SOF ACOGS. Not all teams in all groups mount the optic, but if the loggies have done their job, they have them available.

For what it’s worth, the Dillon-made Miniguns are preferred over the original GE ones because they’re easier to handle — which is relative; it’s a very difficult and intensive weapon to maintain. “The way that GE attaches the backplate, it feels like it’s trying to rotate in your hands” said one guy who attended a maintenance school which was “nowhere near enough time” on the miniguns. The M134 nomenclature is still used, but only when the gun is mounted for aerial use (for instance, as a helo door gun). This is operator-level maintenance disassembly of a Mk 44, NSN 1005-01-576-3284:

Haven’t seen that many parts since BAR days! Note the armorer’s breakfast of champions: Starbucks, Krispy Kremes, Gatling Gun.

Contrary to normal Hollywood practice, the Mk44 is not an individual weapon for a muscle-bound refugee from WWE, but a vehicular weapon. If it has an Achilles’s Heel, it’s the electrical system. The Navy specified paper fuses, and it’s not easily to tell when a fuse is blown… the first thing an SF armorer or 18B needs to do is replace the fuses with similar value ones from the vehicle maintenance shop. Because it’s a 24v system, it adapts readily to military vehicular or aircraft electrical systems, but is harder to install in nonstandard vehicles. (It can be, and has been, done, but it’s a pain in the neck). The weapon system, complete, draws 2,500 watts of power.

After juice problems, the next most common reason for a Mk 44 going silent is ammunition exhaustion. It burns a lot of rounds at a rate of about 3,000 / min cyclic. (The rate is selectable but that’s the standards). It’s often installed in a Mk49 CROWS, which is relatively trouble-free compared to the gun itself, but can also be fired by a double spade grip on the backplate, and that’s one of the more common ways for SF to use it. Found on YouTube, SF at the range:

Basic load is a multiple of 3,000 round ready canisters. (The Vietnam-era 1,000 round cans seem to be obsolete). The cans need to be changed before you shoot up the last rounds in the approximately 14-foot long (~4m) flexible feed chute, or reload will be a slow and exacting experience, and if you are under fire your teammates will call you hurtful names.

Even as the SCAR has fallen out of a favored position as the doorkicker-gun-par-excellence, there’s word that Big Green is buying a quantity of them, and they are being relabeled the CAR because the S in SOF Combat Assault Rifle no longer applies.

SF and all ARSOF loves it when Big Green buys something that we pioneered, because it means we can get more with regular Title 10 appropriated funds and not use our MFP 11 SOF money for that. Sure, it’s all the same tax blood coming from the same taxpayer turnips, but the finite pool of SOF money has to buy everything from TF 160’s next space age flying thing to improved foreign-language training classes. As you can imagine, the fly guys and the language instructors (not to mention futuristic communications and ISR-device users) get bent out of shape when we “misuse” what they know is “their” money merely for stuff to kill the enemy with, which they point out that we can do perfectly well with two sticks of wood and 18″ of twine. So when we get guns that are shared with the big Army, it’s better for everybody: we think it often gets them better guns (they sure liked lightweight 7.62mm machine guns), and we know it gives us more cash to spend on our other priorities that are less in-demand among the general purpose forces (who have their own track record of killing the enemy, after all).

Where We’re Going

That’s anybody’s guess. Wider issue of the .300 BLK upper has been a matter of controversy inside SF — some are strong for it, some oppose it. The guys that have it have been dealing deadly execution with it. But SOCOM has reportedly solicited offers for 25 thousand .300 BLK PDW/CQC kits: with a side-folding stock and a 10-inch .300 BLK upper.

There’s no real interest in piston uppers or 416s. Fanboy stuff for the civilian tacticool community, really. Nobody’s shown us a data-driven test that documents any significant improvement. (Remember, the 416 was bought by SOF ~15-20 years ago to solve a short barrel reliability problem that’s now well-licked in DI weapons).

Magazines are prosaic but they’ve come many miles. We’ve gone from having only a couple of decent magazine choices to a great quantity of types of solid, reliable, consistent-feeding magazines. The days that you had to run steel HK mags because the issue mags sucked so bad are long behind us; even the issue mags don’t suck. The HKs are still good, but why pay the dollar and weight premium? Magpuls are good, too — the Marines are standardizing on them — and they’re not the only good polymer option.

There’s also no real interest in a reversion to 7.62 in any of the current platforms as a standard, baseline weapon. Afghanistan and Iraq/Syria are a bit unusual in offering lots of long-range engagements. Unless their predeployment training dropped the ball (which some units have managed to do), our riflemen across the board are far more lethal than the enemy anywhere inside the 800m envelope. The enemy still deploys (apart from MGs and snipers) weapons that are outranged by our rifles, mostly 7.62 x 39 weapons with short-radius open sights; the AK platform fails to exploit the accuracy potential of its cartridges.

With the war continuing, we may not see major fielding but we’re going to see lots of improved developments. We are currently in a place where some of the last decade’s developments need to be digested and promulgated. We’re not sure where the soldier of 2117 will be fighting, but the odds are pretty good he will be fighting with a weapon that launches metallic projectiles from the shoulder and weighs about 6 to 10 pounds. As has been the case since about 1617.

USMC to Issue M27 More Widely?

A dog’s-breakfast of an article at Marine Corps Times suggests that the Marines are considering issuing the M27 IAR, now issued to squad automatic riflemen, for issue to all riflemen — not all Marines, in the sense of “every Marine is a rifleman,” but to MOS 0311 Riflemen, who apparently haven’t been named Genderfluid Riflepersons yet, in a crushing blow to the one USMC initiative of late unlamented SecNav Ray Mabus.

The 0311 Rifleman, we are assured by no less an authority on all things Marine than R. Lee Ermey as Sergeant Loyce, “is the &%$ing United States Marine Corps.” Let’s pick up a few things from the article, starting with why the Marines love the IAR:

While the M249 can put more rounds downrange, the IAR allowed Marines to provide suppressive fire with greater precision, Marines said.

“It’s been almost a paradigm shift in understanding what suppression is,” 1st Lt. Tom Rigby told Marine Corps Times. “It’s always been understood by the junior Marine that volume of fire and the sound of the machine gun equaled suppression.”

For the love of God, random noise was never “suppression,” but we suppose that’s what the reporter gets for interviewing a lieutenant. “In my experience…” it’s Baby Duck’s First Day!

Only accurate fire suppresses enemy fire. This is not a new discovery… people throughout history have had better luck shooting right at the enemy than sort of at him.

What’s next, on this Baby Duck’s First Day when All Is New? The distilled wisdom of a mosquito-winged PFC, speaking from his six months’ Marine experience?

Well, funny you should mention that:

“On single-shot, you can hit 800 yards no problem,” Lance Cpl. Joshua Houck told Marine Corps Times. “I love that you can go from single shot to full auto with the flick of a switch.”

Gee, what a novel feature. The Marines never had it before… except in the M16A1. And the M2 carbine. And the Thompson Submachine Gun, designed in 1918-1919, and bought by the Marines in the twenties, for crying out loud. But you can’t expect a boot PFC to know that.

Then, on the superiority of the HK 416 (which is all the IAR is) to the M4, the authority they cite is — a long retired Army Major General, a professional camera hound who has zero combat (or even training) experience with either weapon. Seriously, look at this (emphasis ours):

The M27 that the Marine Corps currently uses for the IAR, is “hands down, the best automatic rifle in the world,” said retired Army Maj. Gen. Robert Scales, author of the 2016 book “Scales on War: The Future of America’s Military at Risk.”

“It outclasses the M4 in every single category,” said Scales, who is not affiliated with Heckler & Koch.

FFS, it is an M4, except with two 1980s-vintage improvements, a free-floating barrel and a gas tappet system.

“The key category is reliability — particularly in dusty, sandy, muddy terrain. The HK has a solid rod system, like the AK-47.”

“Solid rod system?” Is that a thing? And no, the HK 416’s gas tappet system is nothing like the AK’s gas piston system. Unlike Scales, we have examples of both, and have shot and maintained ’em. (From a Larry Vickers video, this is the HK 416 gas system).

The M27, sold to civilians and overseas as the HK 416, uses a piston to control the function of the bolt, and that eliminates problems with gas-tube operating systems used in the M4 ­carbines and M16 rifles, according to the company’s website.

“Uses a piston to control the function of the bolt?” This is retarded, although it’s not Scales talking, but the reporter. It’s pretty clear that neither of them has the foggiest notion what goes on underneath the handguards of any modern military rifle.

But hey, Scales does step up to double down on the Full Retard:

If you have a solid rod, then the action can literally blow through things that would normally slow down a bolt action, because you’ve got more mass,” Scales said in a March 27 interview.

This is beyond being stupid about weapons… he’s galactically stupid about physics, too. Hey, we just noticed that there’s a solid rod on all our bolt actions, and you actually have to grab it and waggle it around to load a new round. That definitely slows things down.

“Whereas, the M4 has a floating bolt that’s not attached to the rod. The gas goes down a long, thin tube — and the gas itself blows against another tube on top of the bolt, which throws the bolt back instead of carrying the bolt back.”

Two little sentences, more fail than we can count. Proof positive that one can “be ‘tarded, and still live kick-ass lives.”

Now the reporter gets to to paraphrasing rather than quoting Scales, so you can’t be sure whose retardation is radiating stronger in this particular Superfund Site of a sentence:

The HK 416’s floating barrel makes it much more accurate and stable than the M4, especially in automatic fire, he said.

Aargh.

The rifle also gives troops between 100 and 150 extra meters of effective range than the M4.

Mostly, as Shawn at LooseRounds has demonstrated, because we underestimate the M4 and undertrain with it… but yeah, the longer barrel and free-floated barrel of the M27 are helpful at longer ranges. Where, alas, the terminal ballistics of the 5.56 are comparatively anemic, and where an infantry unit has much more effective weapons, something Scales would know if he were still an infantry officer and not a quote-generator-for-hire.

And let’s close the quotes with another direct quote from Scales:

“It’s the only weapon better than the AK-74, according to people I’ve talked to,” Scales said.

Oh, Lord. “People that he’s talked to.” Well, we defer to that! 

If the AK-74 is so awesome, why is Russia only exporting them to places that get them, essentially, for free, courtesy of hard-working Russian taxpayers? Has he shot an AK-74? Of course he hasn’t! He’s a general, he has people for the shooting stuff. And he talks to people, who may be complete random souls but we’ll defer to him because we are impressed with the Argument from Authority logical fallacy.

If you want to read the whole article, it’s not entirely retarded. There are quotes from Marine Commandant Neller, and those are OK. The reporter has also stealth-corrected his original error in which he said the Marines envisioned issuing the IAR to every mortarman, anti-tank infantryman, etc., while what he meant was that the Marines don’t envision issuing the rifles to infantrymen who are not MOS-designated riflemen.

3D Printed Custom Target Grips

This grip on a Ruger target pistol was made using the latest in additive manufacturing technology.

Here’s a Benelli similarly configured, but with an added shelf to cure “slide bite” that bedeviled the owner…

… and a Russian .22.

Target shooters have long had custom grips made to fit their individual hands. (Indeed, you can buy many exotic pistols with a grip that is fully inletted but externally a block of wood, ready for you to shape it yourself). But it was probably inevitable that an entrepreneur would surface, doing this with 3D scanning and printing: Precision Target Pistol Grips.

After making precision target pistol grips for Air, Standard, and Free Pistols, for a variety of hands and guns for the college team I coach, I’ve recently begun a business doing the same.  Using 3d scanning and printing techniques I’ve modeled many different guns and hands from XS to XL, left-handed and right, straight inset and cross-eye dominant.  Now you don’t have to own a high-end gun to get a precision or  custom-fit grip.

Your grip can be manufactured from either a plant-based polymer (called PLA) in your choice of color or one of three colors of a wood composite that is half polymer and half wood fiber.  In hand, the composite grip feels like a traditional wood grip but one made exactly to your hand.   Best of all, these grips start at less than half the price of a traditional custom wood grip.

Custom grips have mostly been used on very high end Euro target pistols: Pardini, Hammerli, etc. But now you can have the grip that works perfectly on your Free Pistol duplicated (within regulations) for your Rapid Fire pistol, for example. The grips are made of PLA plastic or of a wood composite material that contains wood dust in a PLA binder — and retains the feel and warmth of wood.

For a basic grip, only a few basic hand measurements are needed (how to do that is explained on the site, too). You can also customize your grip with putty or sanding, and send the customized grip in to be scanned and duplicated.

As you might expect, if you’ve been following our writing on 3D printing, one of the greatest benefits of this technology is not its prototyping speed, or its ability to enable “mass customization” (exactly what’s happening here). Those are great features, but the real wonder of additive manufacturing is that it enables technologies that previously didn’t exist. 

Two of these novel developments are a target revolver grip that lets the shooter fire single-action without having to shift his grip at all…

… and an ability to print an “imitation 1911 grip” for a 1911 shooter’s practice air gun or .22, like this very un-1911-like Pardini that now emulates the feel of a 1911A1.

And it’s still “early days” for this technology. Who knows what it will enable next?

More on Cold Forging of Barrels

We’re under unprecedented schedule pressure here, and would like to apologize for delays in the posting schedule, comment approval and responses, and getting Kirk’s symphony-length opuses out of the comment cooler. It doesn’t help that we’ve got to work with crappy satellite internet, which has made us rewrite this post three times. Bear with us and we’ll try to keep the content coming -Ed.

In a comment, Daniel Watters noted that James Higley’s web page had been nuked by the ingrates at Purdue who inherited it, but that had been at least partly preserved by the diligent webcrawlers at the Wayback Machine. Sure enough, Prof. Higley’s page lives on, and there’s a remarkable document there:

Mr. Werner Augustin has considerable experience hammer forging rifle barrels, and he wrote possibly the only technical book on the subject. With his permission, the book is available here in pdf format.

It has far more information, in depth and detail, on the GFM process and how to design for, tool up for, employ, and troubleshoot the process than any extant document, in 36 short pages, with technical illustrations.

Hammer-Schlagzone: Hammer Impact Zone Berührungszone-Dorn: Contact Zone – Mandrel Dorn-Standardposition: Mandrel Standard Position

At the end of the document, Prof. Higley added this:

GFM is the largest supplier of hammer forging machines worldwide with equipment dating back to 1946 (www.agfm.com). The author of this book, Mr. Werner Augustin, was employed for 30 years by GFM as an engineer and cold forging specialist. In 1993, Mr. Augustin founded Augustin GmbH based in Steyr, Austria. The company specializes in tungsten-carbide tooling sales and consulting in cold forging processes. Hence, the author has vast experience in the tooling and processes used to cold forge rifle barrels. Mr. Augustin kindly gave permission for this book to be posted on an open website for all interested parties to share. A copy of the original book was scanned and lightly edited by Professor James B. Higley, Purdue University Calumet, in early 2006.

Mr Augustin’s book is extremely detailed. For example, here is a snippet:

The required material purity is essential in order to achieve a surface quality of the forged groove and land profile as far as possible without segregation lines. These segregation lines have a dark color and appear longitudinally on the barrel.

The more P & S exists in the material, the more the formation of folds can be observed in the entry area of the blank bore to forward of the forging profile.

“P&S” presumably refers to phosphorus and sulfur, two trace contaminants that bedevil steel producers and users.

Of course, this effect of fold formation is increased the greater the diameter difference is between the blank bore and the caliber dimension. The fold formation is moreover increased if the hammer entry angle is laid out too steeply.

That’s OK, as he goes on to provide a troubleshooting guide and some very detailed suggested dimensions for hammer faces.

The problem of fold formation will be the most frequent one when forging cartridge chambers. Thus, for this kind of forging, it is essential to use a high grade of steel. The more homogeneous the material structure is for cold forging, the less risk of cracks which might occur during the forging process. The safety of the rifleman always has priority.

If possible the barrel blank should be stress relieved prior to cold forging, in order to obtain an optimum straightness during cold forging. After forging the barrel should again be stress relieved to make sure that during further processing no stress can be released which would negatively influence shooting accuracy. The material strength of the barrel blank lies between 750 and 1050 N/mm2. After cold forging normally the strength of the barrel material increases by approximately 10%.

And no, that’s not the most detailed part.

Bear in mind that while we’re dealing with GFM machines, we’re dealing with radial cold forging. There’s also rotary cold forging. The difference between the two procedures is what moves, and how. In radial forging, the hammers move radially, and the mandrel and workpiece (barrel blank) rotate as they’re fed in, as in this illustration:

In the rotary forging process, the hammers are contained in a cage that rotates, with the rollers driving the hammers in and out, as in these illustrations.

The mandrel and workpiece (barrel blank) remain in the same orientation as they’re fed in, and don’t rotate.

While radial cold forging was developed by GFM and predecessors in Germany and Austria, rotary forging was independently developed in the USA by Torrington and Cincinnati Milacron and predecessors. The illustrations are from this article (.pdf), linked at Prof. Higley’s page.

Document

Purdue version (still there at this writing!): http://technology.calumet.purdue.edu/met/higley/ColdForgingBook.pdf

Backup at WeaponsMan.com: ColdForgingBook.pdf

How are Hammer Forged Barrels Made? And Why?

A European website has a reprint of an excellent article by Vern Briggs of Ruger and Professor James Higley of Purdue. We’ve discussed the various ways of rifling barrels; we thought you’d appreciate Briggs’s and Higley’s deep dive into the process and technology of the most capital-intensive form of barrelmaking, cold hammer forging. (Actually, it could be hot hammer forging just as easily, as we’ll see at the end).

They begin with a history lesson:

To speed up production, German engineers came up with the hammer forging process to pound machine gun barrels to shape from the outside in. Interestingly, Remington took the opposite approach when it perfected button rifling a few years later by forcing the rifling from the inside out. These two differences play a large part in the behavior of the two barrel types which we’ll discuss shortly.

In the aftermath of World War II, forging expertise ended up in Austria with GFM (http://www.agfm.com/ in the USA), and they have become the leading hammer forging machine manufacturer with machines dating back to 1946. European gun manufacturers began using the technology shortly after the war while American manufacturers didn’t start until the 1960s.

As far as we know, the first use of hammer forging in the USA was by TRW on the US Rifle M14 contract. TRW was selected, in part, because it wasn’t a firearms manufacturer, but instead was a maker of machinery and aeronautical and automotive parts. Ordnance officers thought that TRW might be able to bring down costs and improve quality by applying automotive mass-production technology — and that’s exactly what they did with hammer-forged barrels.

This is a big GFM rotary-forging machine with a robotic loader. GFM stands for Gesellschaft für Maschinenbau

Today, Sturm, Ruger & Company uses 6 GFM machines to make all their centerfire rifle, target rimfire, round handgun, and shotgun barrels. Remington has more GFM machines than Ruger, and other manufacturers have one or two machines each, some from other manufacturers. Hence, there are about 20 hammer forging machines actively producing barrels in the USA with none in the hands of small, custom barrel makers. The machines cost over a million dollars each, so it is no wonder only the largest firearms manufacturers have them.

Doing a little mental arithmetic, we can calculate that the sales of GFM machines to American gun makers only amounts to about $20 million over the past two decades or so, surely not enough to keep a large machinery manufacturer in business. In fact, barrel making is only a small part of GFM’s business; the automotive industry uses many of these machines, especially in Europe. American auto companies are starting to realize the benefits of hammer forging, and more and more forged car parts make their way onto the road everyday. While it won’t ever be as common as milling or turning, hammer forging has slowly become a common process in the manufacturing world.

The precision achievable with these machines is almost otherworldly.

While it seems like a rather crude process to beat the barrel down on the mandrel, the process actually requires quite a bit of finesse. Subtleties provide exceptional control of the bore and groove dimensions. For instance, the mandrel is tapered and can be moved in along the length of the barrel during forging. This provides two advantages. First, by precisely locating the mandrel in the bore, a specific bore size within 0.0001” can be obtained. Second, by adjusting the mandrel’s position during forging, the operator can create a tapered bore.

This was how the German war industries created the Gerlach taper-bore or squeeze-bore weapons during World War II. In essence, they used a tapering (but rifled!) barrel to squeeze down the driving bands on high velocity kinetic-energy rounds (with tungsten-carbide penetrators).

Here is how Daniel Defense makes an AR barrel, starting with steel rod, drilling a pilot hole, gundrilling the bore hole, then running it on the GFM machine, profiling it, chambering, etc.

One of the most interesting scenes (to us, at least) was the toolmaker using a surface grinder to reconfigure and restore the worn faces of hammers. The hammers last about 1,000 barrels before needing maintenance.

American GFM corporation links to a number of videos of these machines in operation. Here’s a sub-5-minute video of how a gigantic rotary forge machine takes a steel tube and forms it into a cannon or tank main gun barrel. It’s just like the Ruger or Daniel Defense process, except much larger — and the barrel preform is heated to roughly 2000ºF and maintained at that heat while being forged.

The Army designed and built its own machine, but it’s clearly a kissing cousin of the GFM hot-forge process.

The strengths of this process are speed and consistency. And the biggest obstacle to using this technology, of course, is the barrier to entry: such a machine is extremely expensive, even if you don’t need one big enough to work on 8″ guns.

A Translucent, .22 Glock?

That’s sure what this looks like:

Where did it come from?

There’s a clue in the pictures, and it’s clearer if you look at this shot of the bare frame…

…bare frames….

…rendering…

…and print in progress.

Yeah, it’s a 3D printed Glock. Cue the media meltdown now.

Yes, it does shoot:

*Update* Test firing the 3D printed Glock frame

Of the test fire, Matt, the maker, wrote:

First test of the frame. Fired prob 10 rounds through it. No issues found with it as of yet. …I was on a schedule and had to leave pretty quick so I ran my tests real quick to see how it looked then took off.

The frame does depend on metal rail inserts, and the designer has promised to release the .stl files… after a frame rail redesign.

Responding to skepticism about the part strength, he wrote:

It would take a long time for the actual frame to brake. Nylon is incredibly strong and specifically this nylon I am using is very close, property-wise, to the nylon Glock uses in their frames and they don’t tend to break very often even after hundreds of thousands of rounds. The first thing to go on my frame would be the rear metal rails since they are held in by a strong glue but have shallow slots since there is not a lot of room back there. I am redesigning the print a bit to allow me to actually put solid, connected rails into it mid print to help alleviate the need for glue since it will always be the first failure point. I am also modifying the design to add rear nylon rails along with the metal ones because the combo of nylon and metal on the front is proving to be very resilient and precise vs the only metal rails in the rear.

The material he’s using is Taulman Nylon 910.

…the easiest nylon I have ever worked with. I made the dehydrator they actually have on their site and that thing is amazingly good and cheap… then I just ran the nylon on the recommended settings and it was already pretty good then I just tweaked it a bit with calibration to get my printer zeroed in and that frame was printed with no issues at all, other than some minor warp when it cooled. And as a minimum 10 hour print it had a good amount of time to mess up.

He explains that the Nylon solves the single greatest bugbear of highly-stressed 3DP Fused Filament Fabrication parts, layer stratification and delamination:

Normally, yes, 3D printed would have a weakness in the layer adhesion. Nylon specifically though has incredibly good layer adhesion when printed properly. The times I have managed to break nylon parts they have never delaminated and always broke across laminations randomly. It is pretty much the way even an injection molded nylon part would break.

He’s not done:

The next iteration of the frame will be even better and will have an even longer potential life with no need for repair. I have identified a couple places that end up being a pain when its printed but don’t matter as much when injection molded, so I am working around them to make it specifically a solid 3D printable frame. I also have a few ideas for alternate frames based on the pistols in mass effect.

For more information:

 

Tons of Details on German WWII MG Tripods: “Lafettes”

We can’t discuss machine guns on this site without someone — usually Kirk — reminding us that the GI M122 tripod is rudimentary junk, and the class of the tripod world was the German Lafette 42. We’d like to steer those interested in these ‘pods to the incredible Lafette 34/42 web page of “Bergflak (“Mountain AA”) who is posting his work in progress on these amazing feats of German engineering.

How complicated was it? These are the parts of the lower half of the MG.34 Lafette. (The lower half of the MG.42 version was fundamentally identical).

Not complicated enough for you? Here’s 100-odd more parts from the Oberlafette, or upper half.

But wait, there’s more! 70-something parts that comprise the T&E mechanism.

Here’s a brief blurb from Bergflak:

The MG Lafette was a pretty complicated piece of machinery for its time. Some would say “typical German over-engineering”. It contains several systems that all work together. The difference between the Lafette 34 and the Lafette 42 is mainly the cradle. The weapon mounts and the trigger mechanism are simpler on the MG42 cradle. In addition it has a different bolt box. Everything else seems to be identical.  This page will only describe the Lafette 34. The change from the Lafette 34 to the Lafette 42 will be fully dealt with on the Wartime development page. On this page I will briefly explain the function of each of the components that make up the Lafette. For an even better and deeper understanding of the components you must visit my page Extreme details or the pages about Evolution of the Lafette (when they are finished).

via MG34 Lafette construction and details.

These pages explain which each part does, and pages on the evolution of the MG-34 and MG-42 Lafettes actually are complete now. Unfortunately, the page explaining the usage and employment of these tripods is not yet complete.

The whole site is worth reading already, and it stands to reason that as more information is acquired and analyzed, the site will just keep getting better and more useful.

More on the Czech/German AT Rifle

Our recent auction post reminds us that (1) we have to come up with some better way of flagging more interesting auctions and (2), and more to the point of this post, that there’s a lot of interest and misconceptions about the Czech-German AT rifle featured at one upcoming auction.

First, this 2015 post here has some background on rifle-caliber-yuuuge-case AT rifles, like the German and Polish variants, and their rounds. (This archived external page also covers the round). The Germans chambered this rifle in their standard wartime 7.92 x 94 mm P318 round, which was used in the standard German PzB 38 and 39 AT rifles. The round was capable of 4,000-plus fps from a long barrel and the most common ammo was a tungsten-cored kinetic penetrator. P.O. Ackley, eat your heart out. Barrel life was pretty short, but if you’re going to shoot a rifle at tanks, it’s not the life of the barrel that should be worrying you.

(The Russian site that cartridge picture is from appears to be down now, unfortunately).

Those rifles operated by a dropping block, like an artillery piece (or early breechloader), and their principal mechanical difference was that the PzB 39 was manually operated, replacing the “semi-automatic” (in artillery terms) automatic opening and ejecting of the PzB 38.

The Czech rifle used completely different principles, and as proposed for Czech service a different cartridge.

In fact, the Czechoslovak Army experimented with a variety of anti-tank rifles in the 1930s, as part of a campaign to improve AT defenses overall. Many Czechoslovak officers put their faith in conventional anti-tank artillery, but others pursued the AT rifle. Many versions were tested including Josef Koucky’s’ ZK 382, a bullpup repeater which fired a unique 7.92 x 145 mm round, further ZK single-shots ZK 395 (12 mm x ?) and ZK 405 (7.92 x ?), the ZK406 repeater and 407 self-loader the “Brno W,” the Janeček  9/7 and 15/11 mm Gerlach-principle squeeze bore, and several 15mm designs, including vz. 41 single shots, and a bolt-action magazine repeater which was supplied to Italy (in only 15 units) and possibly Croatia. The 15mm guns used an AP version of the 15 x 104 mm round used in the Czechoslovak vz. 60 heavy MG, produced primarily by the British under ZB license as the 15mm BESA. The Czech engineers then reworked into the vz 41 in 7.92 x 94 for the occupiers, specifically, for the SS.

During all this experimentation, Czechoslovakia was dismembered and its Czech provinces occupied. The best was the enemy of the good; nearly a decade of experimentation in AT rifles wound up yielding absolutely nothing for the Czechoslovak Army. (It was a moot point, perhaps, as despite its strengths in tanks and artillery, there was no resistance to the Nazi occupation.

Most of the elite of the Czech arms design industry worked on these rifles at one time or another. Vacláv and Emanuel Holek worked with Koucky at Zbrojovka Brno; Jiri Kyncl worked with Janeček.

By the time the SS received their rifles, they were already hopelessly outclassed by improved armor, and among Speer’s actions in his attempt to rationalize the chaos of the German and occupied territories’ arms industry was to discontinue production of the 7.92 x 94 Type 318 ammunition.

The M.PzB.SS.41 was supplied in a wooden transfer and storage crate containing the rifle, two spare barrels, and four magazine boxes containing five magazines each. There were some variations in minor features (bipod, muzzle brake) during production. Of some variants, only photographs or documents survive. We have found no reports of combat effectiveness.

All of these AT rifles are rare today, the German guns existing in single-digit quantities (the mass-produced PzB 39s were recalled during the war and converted to grenade launchers, the GrB 39).

Sources

  • Dolínek et al. Czech Firearms and Ammunition: History and Present. Prague: Radix, 1995.
  • Hoffschmidt, E.J. Know Your Anti-Tank Rifles.  Stamford, CT: Blacksmith Publishing, 1977. (A .pdf of the chapter of this out-of-print book on this rifle is attached: MPZB41 comp.pdf)
  • Šada, Dr. Col. Miroslav. Československé Ruční Palné Zbrane a Kulomety. Prague: Naše Vojsko, 2004. (pp. 139-142, 197-198).

Update

Well, this is embarrassing. Never hit “schedule” or “publish” on this one. -Nose