Category Archives: Industry

USMC IAR Reliability Testing Results

A friend of a friend of the blog FOIAd this information, which took him two requests. The first produced the Round One reliability testing, which downchecked 6 of the 10 submissions. During the first-round test and data analysis, the submissions were blinded by using a code letter ID from A through J. In the results below, the producers of the four proposals which advanced to Round Two are shown, while the downchecked candidates are still indicated only by code letter.

Ultimate winner — the HK M27 IAR, a version of the company’s HK 416 AR knock-off.

Results from Round One, in 2008:

e. All participants submitted three samples for testing.

f. Results for all Class I and II failures are listed below across all 3 UUTs from 9 of the 10 IAR Bid Samples.

  1. Colt proposal A: 60 Failures
  2. Colt proposal B: 28 Failures
  3. Competitor C: 23 Failures
  4. Competitor D: 78 Failures
  5. Competitor E: 39 Failures
  6. Competitor F: 12 Failures
  7. Heckler & Koch Defence Inc. proposal G: 27 Failures
  8. Competitor H: 124 Failures
  9. FN Herstal proposal J: 26 Failures

g. The 10th IAR Bid Sample, Competitor I, was determined unsafe for live fire due to a lack of proof marking. Live fire testing was not conducted.

Kind of a raw break for that unfortunate competitor, Code Letter I.

Note that some of the rejected proposals (C, E, F) had fewer failures than the ones that proceeded. This is presumably due to the distribution of the failures. (If you have only a few failures, but they’re take-the-gun-to-the-bench failures, that’s a whole other thing than a higher quantity of simple failures that are rectified in seconds by operator immediate action (a la SPORTS drill on the M16/M4 series).

This is the Round One definition of failures by class:

Reliability Testing

The Unit Under Test (UUT) shall have a Mean Rounds Between Failure (MRBF) of 900 for Class I and II failures combined (Threshold), 5,000 MRBF (Objective).

  1. Class I failure: A failure that may be immediately corrected by the operator within 10 seconds or less while following prescribed immediate action procedures.
  2. Class II failure: A failure that may be corrected by the operator, and that requires more than 10 seconds but not more than 10 minutes to correct (less the TM/OM defined cool down period if a hot barrel condition exists).  Only the equipment and tools issued with the weapon may be used to correct the failure.

A very similar definition of failures, with a third, more serious, class, was used for Round Two in 2009.

Reliability/Endurance Testing Mean Rounds Between Failure (MRBF)

a. Three Units Under Test (UUTs) were provided for each model under evaluation.

b. The UUT shall have a Mean Rounds Between Failure (MRBF) of 900 for Class I and II failure combined (Threshold), 5,000 (Objective). The MRBF for Class III failures shall be 15,000 (Threshold), 20,000 (Objective).

  1. Class I failure: A failure that may be immediately corrected by the operator within 10 seconds or less while following prescribed immediate action procedures.
  2. Class II failure: A failure that may be corrected by the operator, and that requires more than 10 seconds but not more than 10 minutes to correct (less the TM/OM defined cool down period if a hot barrel condition exists). Only the equipment and tools issued with the weapon may be used to correct the failure.
  3. Class III failure: A failure of a severe nature. The failure (1) can be corrected by an operator but requires more than 10 minutes; (2) cannot be corrected by an operator and requires assistance (no time limit); or (3) requires higher level of maintenance or correction by an authorized operator cannot be accomplished because of unavailability of necessary tools, equipment, or parts.

This table is taken from the FOIA release, but we have added a column identifying the firearms, which in this test were coded 09 (presuably for the fiscal year) and a letter, thus 09A, 09B, etc.


Manufacturer MRBF
Class I and II
Class III
Barrel Life




60,000 1800
09B Colt 1,277 15,000



FNH USA 5,000 N/A*


09D HK USA 1,622 20,000


Some interesting results here. The FN entrant had the highest rate of relatively minor Class I and II failures, but the lowest rate — zero — of Class III failures. (That’s why it’s “N/A”. You can’t calculate an MRBF with zero failures). And the HK example was distinctly mediocre compared to these competitors, on this one measurement. Conversely, it had far and away the highest barrel life — an important statistic for the always-broke Marines.


Apologies to all for leaving off the document. This was actually two separate FOIA releases, of three and two pages, but I’ve combined them into one document and OCR’d them for your convenience (well, I also OCR’d them so I could pull those quotes above).

The initial page with the ID of the requestor has been deleted as he has requested privacy.

IAR Reliability Testing FOIA Release.pdf

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.


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.

Wait, French CT is Going to 7.62 x 39? Whaaaat?

This brief story suggests that the French Gendarmerie’s national CT organization, the GIGN, is replacing their HK 416s with CZ 806 Bren 2s… that’s possible.

Except that the article is quite explicit that they’re going to a new round: the Soviet 1943G 7.62 x 39 mm intermediate round. This guy:

The French National Gendarmerie Intervention Group (GIGN) has ordered a new standard issue weapon.

It has selected the Bren 2 assault rifle from Czech company CZ. The company told Shephard at the SOFINS exhibition that the GIGN has selected the 7.62 x 39 mm version of the rifle and placed an initial order for 68 units earlier in 2017.

Additional procurements are slated to take place in the near future with the aim of replacing the majority of the H&K 416s currently in service.

Supposedly, the caliber decision was made early on, before the rifle decision, and in fact, long before CZ entered the competition.

The decision to adopt the Bren 2 was the result of a process that began in 2015 after the Paris attacks in January that year. Faced with terrorists equipped with bullet-proof vests, French gendarmerie and police intervention units found that 9 mm weapons had little efficiency in such situations and that 5.56 mm ammo lacked the necessary stopping power.

The CZ spokesperson said that the GIGN identified a need for a new weapon able to fire a heavier bullet. The 7.62 x 51 mm calibre had the suitable characteristics but the weapons for this calibre were considered too heavy and bulky for efficient close-quarter combat.

Thus, GIGN decided to evaluate assault rifles chambered in the 7.62 x 39 mm calibre instead and undertook trials throughout 2015 with a variety of weapons.

The CZ 806 Bren 2 does have a French connection already. It was developed from the CZ 805 Bren with a view to the French rifle competition, but it was not ready in time. The French adopted the 416; the Czechs adopted the Bren 2 in place of the earlier Bren, and the rifle has had some export success.

But the 7.62 x 39 mm round decision rang so false to us that we initially assumed that this article was an April Fool’s Day joke. It can’t have been, though: it was published 30 March.

Not to mention, the 7.62 x 39 mm model is … well, look at it. It was spawned in the cauldrons of the five Lee Sisters: Ug, Home, Ghast, Beast, and Gnar.

Anyway, you can Read The Whole Thing™, and form your own opinion. So far we’ve found no support for this at CZ, on French government sites, or, in fact anywhere. Can anyone confirm or deny this story?

Let’s Dive Deeper on the CZ 122

One of the CZ 122 images from Pazdera’s book.

The CZ 122 we recently mentioned here is a bit of a mystery in the United States, as it was never imported here; some were brought to our friends in Canada, but only a few; and the modern rimfire pistol is not available even in Europe now. What happened?

We turned to a relatively recent book by Czech weapons historian David Pazdera, Legenda Jmeny CZ, or in English, A Legend Called CZ. This coffee table sized book is an illustrated history of CZ from the 1930s to date, with a few sparse areas and holes conforming to issues of Czech historiography, but extremely comprehensive coverage of Cold War and post-Cold War CZ products. Sure enough, Pazdera has the CZ 122 covered on pages 325-328. We were on our way out the door on a road trip and couldn’t bring Pazdera’s mighty doorstop of a book, nor had we the time to fire up the Fujitsu and scan the relevant pages properly, so we photographed the pages and précis the information here.

The CZ 122 was the product of designer Stanislav Buran, who was not actually a designer, but the head of a manufacturing engineering section. The project began in the 1990s with the idea for a “simple and cheap” .22 rimfire pistol, to plug a longstanding gap in the CZ product line. But his initial design was a far cry from the pistol that finally reached production. The CZ 94, prototyped in 1994, looked much like any of the last century or so of sporting .22 automatics, with a hint of Woodsman or Hi-Standard ancestry, and a splash of modern Eurodesign:

The CZ 94 is described by Pazdera:

It was a simple and cheap pistol of the lower sporting category, usable for fun shooting or target practice. It had a fixed barrel, and unlocked (blowback) breech, a single-action trigger mechanism and an internal striker mechanism, The  magazine capacity in the final version was 10 rounds. Particularly unusual was the magazine release on the front side of the frame inside the trigger guard.

Buran continued to develop the idea of a simple, inexpensive rimfire pistol, with the help of Vojtech Anderle. It evolved through several prototypes. One thing that changed — a lot — was the magazine catch, which first moved to the classic Euro/Hi-Standard position at the base of the grip, and then to the classic Browning position at the junction of the trigger bow and the grip frame.

As you might expect for a design that began with a manufacturing engineer, production engineering and cost control were in the design mix from the start as CZ 94:

It’s assumed that for manufacturing, a frame of aluminum alloy or plastic, of which (the plastic) another set of parts might also be made. In addition, there was also expected to be frequent application of stamped sheet-metal parts (trigger, disconnector), and parts from the Kadet small-caliber adapter (barrel, extractor, firing pin, magazine) and from the standard CZ 75 model (hammer, sear).

In 1995, the pistol was extensively redesigned by industrial designer Vojtech Anderle, who drew six sketches, from which one was selected, leading to six more design studies based on that. The final styling was incorporated into the CZ 122.

In the CZ 122, compared to the CZ 94, the angle of the grip was changed to 108º,

The frame of the new model got a slide release. For that reason, the weapon got an old-fashioned magazine release at the base of the magazine well. The barrel was pressed or molded into the frame.

Initial tests found the plastic-framed prototypes more reliable than the alloy-framed ones, but “for technological reasons” the alloy frame was selected. In 1998, designer Petr Pöschl was tasked to finalize the pistol and bring it to production.

The CZ 122 was produced from 1998 to 2002, and then again from 2004-06, but only 6,192 examples were manufactured. All have the alloy frame. The breakdown between European-mag-release and Browning-mag-release production is unclear.

Pazdera says this about the design’s benefits:

The modern design of the CZ 122 Sport Pistol was meant in part to be reminiscent of a modern service pistol, but the weapon was also able to feature a series of sporting features: fully adjustable LPA target sights, single-action trigger mechanism with an external hammer of the sporting type, and a trigger with a straight tongue and screw-adjustable travel.

If it was such a carefully designed pistol, why weren’t more of them made? The pistol performed well — usually. But it was finicky about ammo, and launched into a glutted market full of established target pistols.

The accuracy potential of the weapon was solid, for example during tests carried out during the year 1996, it was possible to achieve groups of 25 mm (tn: less than 1″) at 25m (highly dependent on the ammunition used). The weakness of the one-twenty-two was inconsistent reliability. This compared with the strong market positions of quality competitors had as a consequence unsatisfactory sales numbers, which led the Uhersky Brod company to definitively wrap up this program in the first half of the first decade of this century.

In the modern era, of course, CZ-UB is a profit-making enterprise, and a slow-selling pistol is a waste of manufacturing resources. Worse, a pistol that is prone to fits of unreliability and that is finicky about ammunition — even though that’s not a rarity in the rimfire market — risks the reputation CZ has built up for almost a century. As a result, the CZ 122 is a rarity, enjoyed by those who’ve found the right ammo, and coveted by CZ collectors.

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?

Barrelmaking, a Century Past

This booklet at includes reprints of several Machinery articles from the First World War period, describing the industrial manufacture of rifle barrels at the time. The complexity of the task and its many operations are clear, plus, of course, there were various methods of cut rifling, but no other method of rifling, because button, cold forging, and electrochemical processes had yet to be applied to this task.

And before you could rifle, you must drill, which had its own problems.

The first article is on the manufacture of the Lee-Enfield barrel, and begins:

The most difficult part of a gun to make is the barrel. A knowledge of the conditions under which it will be used, a thorough acquaintance of the principles involved, and sound and accurate machinery are essential before a barrel can be made successfully.

Naturally, the sequence of operations and methods used are not identical in different factories, but there are definite stages in its manufacture which all makers must follow. After being centred, the surface of the barrel forging is rough turned to relieve it of outside strains, and briefly, the chief operations following are: drilling, finish turning, grinding outside, fine boring, rifling, lapping, screwing and chambering.

There are other operations that are only used in contingencies, for example, barrel straightening. The book is well worth the read!

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 ( 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.


Purdue version (still there at this writing!):

Backup at 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 ( 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.

Understanding CZ Test Targets

In accordance with longstanding European gunmaker custom, CZ ships a test target with its pistols. These seem ridiculously simple, but there are enough people asking about them in online forums that we thought we’d explain them. We usually have a few CZs with boxes and paperwork around the house…

Don’t get too excited, they’re not NIB old stock (well, most of them aren’t). (If you look real close to the right of the CZ-75 box, you can see a current CZ-UB box that almost exactly matches the black background. Adventures in photography). While we don’t have anything from the 70s or earlier represented here, we do have (oldest first):

  1. A CZ vzor 70 in 7.65 mm manufactured during the pistol’s production twilight, in 1980.
  2. A CZ-83 in 7.65 mm manufactured during the pistol’s production startup.
  3. A CZ-75 “Pre-B”, manufactured in 1987, prior to mass importation to the United States;
  4. A CZ-75 P-01, manufactured in 2015, which is typical of current CZ-UB production.

The first three pistols were manufactured during the Cold War era and the P-01 is contemporary. All four were probably scheduled for production with a view to exportation, although both the vz. 70 and the P-01 were also the standard pistols of the national police force, and when this CZ-83 was made, there was some thought that the Verejna Bezpečnost (police) would adopt it order to retain the 7.65 caliber.

It is our understanding that all targets are shot rapidly, from rest, at 25m, although only some targets are labeled with distance; and that Sellier & Bellot ball ammunition is customary.

We’ll now look at the targets in the same order. The targets are of three different types: the vz. 70 has a small polygonal aiming point inside a rectangular target area, the target used by the CZ-75 and -83 has a rectangular aiming point with the center of desired impact on its bottom edge and a circle centered on that point describing the desired impact area, and the P-01 target is a modern digital rendering of the firearm’s performance on an instrumented range.

  1. The vz.70 target is actually labeled vz.50. This makes perfect sense, as the two pistols have only cosmetic differences; most of the running changes in these small police pistols were made during the vz. 50 years. A late vz. 50 is more like a vz. 70 than it is like an early vz. 50. There are six shots on the target, one a flyer to the left. The legend at top reads: PISTOL 7.65 MODEL 50 and PISTOL NUMBER 652090. The legend on the bottom reads DATE: 29 Dec 1980; SHOOTER: Zemek (with two partial, illegible rubber stamps, one circular and one a signature), and OTK with a rubber stamp which may be the “kissing lips” we discuss below. We would welcome any insight to the meaning of the acronym OTK, but suspect it’s some type of inspector.
  2. The CZ-83 target is a CZ-75 target with the -75 legend scratched out with black ink, and a CZ-83 legend rubber-stamped in place. Whether a specific target was developed for the CZ-82/83 series is unknown; it’s possible, as this pistol has a four-digit serial number flagging it as first year production. The CZ-75 would have been the main export product of the Uhersky Brod plant when the -83 was introduced, and these targets would have been in daily use. On this target, the pre-printed CZ-75 lines (which you can read on the next target) are inked out, and a rubber stamp says Pistol čz model 83 caliber 7.65 mm. Below the inked-out CZ-75 lettering is Distance 25 m, and to the right is Pistol Number 002846. The legend on the bottom reads Date (blank) Shooter (stamp looks like JBICHR [?]), and OŘJ with a stamp we call the “kissing lips” but appears on magnification to be a blurred-out stamp that once had numbers or characters within it. It seems logical that OŘJ also refers to some inspector or inspection title, but again we do not know the Czech acronym.
  3. The target with the 1987-production CZ-75 (pre-B, which dates to 1992) is the same basic one used for the CZ-83 above, obviously without the CZ-83 adaptations. The legend inked out in the -83 target is seen to read PISTOL ČZ Model 75, Caliber 9 mm Parabellum, and the SHOOTER stamp at bottom center reads FICE[?]NC. The OŘJ stamp can be seen to be a circle with illegible characters inside (we liked it better when we thought it was kissing lips! From Moravia with love!). Seven shots appear to have hit this target, unlike the six of the two earlier ones. It is possible that this target is more “weathered” than the older CZ-83 target because the gun reached its end buyer in 1987, while the CZ-83 remained in one warehouse or another until 2017.
  4. The P-01 is a modern computerized target that depicts the fall of the shots graphically on an ordinary sheet of A4 computer paper, and contains a great deal more information than the old targets. There is no point in translating any of the Czech, as CZ-UB has helpfully done it for us. This target represents the impact of five shots by white circles. The blackened circle is the calculated center of the group.

That the new targets are labeled in English as well as Czech is a nod to CZ’s export focus these days; printing them on an ordinary A4 sheet of computer paper and generating them by computer saves time and money at a busy factory, yet gives buyers confidence that their firearm has been tested and worked. (Europeans still have to proof-test their firearms, but we suspect many American firearms leave factories without every cycling a live round).

The Cold War era targets are (sparsely) labeled in Czech only, and are printed on extremely coarse and flimsy Warsaw Pact era paper, which has, as you can see here, yellowed to one degree or other with age. They do have a certain character. If we didn’t want to keep these in the boxes the firearms came in, we might just frame them. How much of the dirt, oil etc. on these fairly dirty targets came from the range and how much from the intervening decades of handling is anyone’s guess.

All targets are serial numbered to the guns, usually with blue ballpoint ink, and have a space for the technician who fired the gun to stamp his name and the date. Both of these stamps are seldom present, but the serial number has always been.

One open question is whether targets like these were furnished with domestic police and military firearms. Our tentative hypothesis is that they were not; instead, the military (etc) acceptance stamp went on when the ordnance officer was satisfied, and there was no point in retaining a target beyond that. None of the CZs we have with Czech military or police acceptance marks came with targets, but all were used (most, well-used) when we acquired them.


We thought that we’d add this: if you’re lucky enough to have a date stamp on your CZ test target, the month will be abbreviated in Czech. Here is a table of the Czech months and the standard abbreviations for those months, which CZ used on its stamps.

Czech Months

English month Česky (Czech) ČZ Abbreviation
January leden led.
February únor ún.
March březen břez.
April duben dub.
May květen květ.
June červen červ.
July červenec červen.
August srpen srp.
September září zář.
October říjen říj.
November listopad list.
December prosinec pros.

Watch out for June and July!

Too Busy To Write, Here’s Sumdood’s Video (Ian on Colt)

Here’s Ian of Forgotten Weapons with a capsule history of Colt, currently holding down the title of the Most Mismanaged Company in the Gun Racket. Seemed timely, with Colt having purged the Custom Shop lately, in an overall downturn in the industry that has seen Remington lay off a couple of hundred employees, mostly factory workers in Ilion, New York, but also including a senior executive bloodletting. Can more drama for Colt be right around the corner?

Some day, B-School students will study the machinations of the last few rounds of Colt owners… if the guys studying them aren’t law students doing a block on white-collar crime.

But through all that, the company has made some fantastic guns. As the current owners seem intent on demonstrating, there’s a lot of ruin in a great marque.

You can find Ian’s videos on YouTube, but the quality of the videos is better, and the advertisers pay him better, on You do want him to get paid, right? Any time there’s nothing happening here, go to Full30 and watch some of his videos. He needs the money!