Category Archives: Rifles and Carbines

How Armalite (1955-60) Made Stocks & Furniture

The first combat weapon associated in the gun culture’s hive mind with plastic stocks? No question, it’s the AR-15. But the AR-15 wasn’t first. Before making its AR-15 prototypes, Armalite, then of Hollywood, California, made the stocks for the AR-10 — and stocks for even earlier sporting guns.

The Background

While Armalite claims the mindshare, it wasn’t the first by any means. As early as World War II, Springfield Armory developed a phenolic plastic stock for the BAR that was used on production guns beginning some time in 1944. It also made experimental Garand stocks, and would probably have made production stocks, or farmed their production out to industry, for the millions of M1s that would have been needed for the invasion of the Japanese home islands.

But Springfield was trying to do something different from what Armalite was after. The national armory wanted another material for stocks that would be stronger at the same weight. It was not until late in the M14 project that Springfield managers realized that fiber-reinforced plastic enabled them to make stocks with equivalent strength to close-grained walnut, but at much lighter weight.

The Armalite Stock Patent

While Springfield Armory backed into the discovery that composite stocks could safe weight, Armalite didn’t take that long to arrive at the epiphany. They were always about saving weight (that was the “lite” in their name), and they always intended to do it by adapting aerospace materials to the stodgier world of firearms production. Unlike today, the aerospace industry was largely located in Southern California, and it was one of the region’s largest employers — possibly the largest. Aero engineering talent was living in every street; people familiar with the latest alloys, composites, manufacturing process, and substantiation methods were everywhere. The AR-10 would be made from an aluminum alloy forging, just like a landing gear strut or a propeller hub. And its stocks would be made from the new wonder composites: resins of urea, phenolic or melamine, sometimes reinforced with fibers, adhering to an expanded polystyrene foam core.

As early as 1951, Armalite’s George Sullivan applied for a patent showing several methods of making a gunstock with a plastic skin and plastic-foam filling. (The patent was granted in 1956). This is the method that he claimed was in most practical use at Armalite at the time:

Another method of fabrication and the presently preferred one would provide for the making of the skin in, say, two parts or halves; adhering the two parts together to form the completed skin, and finishing the gun stock by casting the plastic core material into the completed skin  wherein it will expand cellularly and adhere to the skin. The two halves of the skin  can be produced by using a conventional mold or die as illustrated in Figure 5, laying and clamping if desired a sheet of thermoplastic skin material over the die, heating the same with appropriate heating elements  until such time as the material is softened and flexible, and then drawing the material until it conforms to the inside’ contour of the die by using suction pressure between the cavity and the sheet of material; its final shape being represented by the dashed line. The two parts thus formed may be adhered together by using standard and conventional cements, after which the completed shell is filled with the cellular plastic core as explained above. An appropriate material for the skin is a thermoplastic sheet of tough, synthetic, rubber-like plastic such as is manufactured and sold by the U. S. Rubber Company under the tradename Royalite; this material being particularly advantageous in that it softens at reasonably low temperatures, cures promptly and does not require the use of a parting material to prevent sticking to the die or mold. I have found it possible to form both halves of the skin at one time by mounting the two dies together with sheet of material  for each die there between; heating the same by inserting the dies into an oven or by pumping heated air into the cavity  until such time as the material is softened properly so that the same can be drawn into proper shape by means of the suction pressure. This procedure permits the foaming operation to be done immediately, thus producing substantially a completed gun stock upon removing the article from the die. The flash can be trimmed off and minor finishing techniques applied.

It sounds very space age, but the early stocks didn’t hold up all that well. This Portuguese AR-10 on a semi receiver has, unlike many, pristine metal and a shiny bore, but its original furniture has been replaced by homely replacement wooden stocks, because the original ones didn’t survive the fighting in Angola.

ar-10_porto_right_side

Sullivan went on to say that the mold (die) material could be plaster, metal or plastic, suggesting “Plaster of Paris, Kirksite, or sprayed metal and Reslyn, a phenolic casting material.” Some of these materials and trade names from the patent are no longer in use. The patent also goes into some depth about the chemical formulation of the foam base and reactant (the foam was produced at room temperature), and suggests that the skin might be equally “a polyester resin by itself or in combination with fiber additives to form a resin-impregnated fibrous material”.  Early AR stocks and grips appear to be polyester resin with what appears to be cotton fibers from chopped-up matting.

US2753642-0illustrationThe resin-skins over foam core was being used at that time by German sailplane builders, and would by the end of the sixties be adopted by an aeronautical engineer named Burt Rutan. The difference between the gun stocks produced according to the Sullivan patent, and the famous Rutan moldless foam construction process, is that Sullivan envisions defining the shape by forming the skins, and expanding the foam inside; where Rutan cut blocks of exopanded foam to shape, and then skinned them, making the process self-jigging and requiring no female mold or die. Like the Sullivan process, the Rutan process can be improved with vacuum, but it’s not necessary.

A 1960 Guns Magazine showed someone’s hands pouring resin into a stock mold, from a cup, just as is shown in #12 of Fig. 2 in the patent. (US 2753642 A, Gun stock of expanded cellular plastic material).

1951 – The Sullivan Handguard (Forearm)

Sullivan had many other patents on guns, cars and even aircraft (the twin-boom cargo plane with a central pod with a rear door was his, US Patent 2,367,538). And he also had a patent for the AR-10 handguard, specifically. This was, as we’ll see, the first of many AR handguard patents.

Sullivan’s handguard didn’t exist in a vacuum, of course. Slightly ahead of Sullivan, Springfield Arsenal’s René Studler had filed a patent for one thing people often think of as an AR innovation: a metal heat shield inside a handguard. Studler’s patent drawing showed his heat shields inside the standard US service rifle of the day, the M1 Garand (US Patent 2,674,822, Forearm and handguard protector).

The Sullivan handguard patent, filed in 1951 but not granted until 1957, is very close to the final AR-10 handguard.

Screenshot 2014-01-13 22.33.42

 

The holes — 8 each above and below the barrel — are intended to allow hot air to flow out the top of the guard, letting the low pressure this produces draw ambient (and cooler, therefore) air in through the bottom holes. The patent goes into some depth about materials for the guard itself — which is meant to have epoxy (isocyanalate) skins and a core of low-density, insulating foam — and the internal aluminum heat shields.

The deep fluting here is one difference from the production AR-10 guards, but the guard’s annular shape and taper are near final. Compared to a traditional walnut forearm, this concept was a multiple win: it was lighter, more durable, did not smoke (unlike linseed-oiled wood), and insulated better. If it had a problem, it was that its annular shape required the dismounting of the entire front sight base and/or removal of the barrel from the receiver to remove and replace the guard. This problem persisted through the production life of the original AR-10.

1960 — Stoner improves the handguard

By 1960, Armalite had solved the problem of handguard removal and a new patent by Gene Stoner, filed in June of that year, shows a handguard closely resembling the one shipped on millions of M16s and M16A1s, although the drawing looks like it may have been prototyped on an AR-10.

Screenshot 2014-01-13 22.55.16

Of course, that could have been a very early AR-15 in the illustration as well. By 1960, development of the smaller AR was underway. The narrow front sight base is why we think AR-10, but some AR-15 prototypes also had these. After all, every firearm Armalite built in this Hollywood and Costa Mesa era was essentially a toolroom prototype.

The patent (US 3,090,150, Hand Guard Construction), was assigned to Fairchild, which had bought Armalite. This patent describes the standard M16 handguard through the early 1980s and introduction of the M16A2.

The patent also made a claim that was inherent in Sullivan’s design, but not claimed by Sullivan at the time: the convective cooling produced by the upper and lower cooling holes in the handguard.

1959-60: The Artillerie Inrichtingen / Portuguese Handguard

Shortly after Stoner’s filing of the patent above, Marinus A Bakker of the Staatsbedrijf Artillerie Inrichtingen of Hembrug-Zaandam, Netherlands, filed an AR-10 handguard patent (he actually filed it in the Netherlands in September 1959, but in the USA August 1960). While the original Sullivan patent resembled the Sudanese contract AR-10s’ guards, Bakker’s is clearly the Portuguese contract handguard. His objective, according to the patent application, was much like Stoner’s: to produce a handguard that could easily be removed without having to conduct major disassembly of the rifle. Bakker further posited that air would enter the forward, metal, part of the handguard, where the barrel is hottest, and then flow back and out the rear of his handguard.

Screenshot 2014-01-13 23.25.09

Interesting to note that Bakker’s patent drawing (US 3075314 A, Hand Guard for Rifles) shows a front sight base with no gas adjustment. The rifles AI would ship with this style handguard would have a gas adjustment to allow firing of rifle grenades with blanks. (It would be interesting to conduct some firing tests with a smoke generator, as used in wind tunnels, to study the convective airflow of different handguard designs).

There were more handguard patents, and more evolution still to come, but we’re now up to date with the AR-10 and the AR-15 through the life cycle of the M16A1.

In Retrospect

The story of Armalite stock and handguard design is a story of talented engineers pushing the limits of technology and starting with a clean sheet, first-principles review of an area of gun design that had done things “the way we always have done it” for, literally, centuries. This was consequential engineering: when the first Project Agile contract dropped, the AR-15, future M16, was the only service rifle in the world with synthetic furniture. But in the 21st Century, every military rifle in the world owes at least a little something to these venerable, and now, expired, patents you see here. Russia, with its endless Siberian expanses of birch forest, and stolid peasant conservatism, at least with respect to weapons design, held out longest of major arms makers.

Returning to the inventor we began with, George C. Sullivan had at least three more patents of interest, but not to the production AR-10 or AR-15: one was for the stock of the AR05 survival rifle (very similar to that of the AR-7, a lasting success), one for the folding buttstock of the AR-16/-18, and the last, for somewhat less of a success: an aluminum gun barrel. But that’s another story.

 

 

Range Report

Sunday, went out to the range with Kid. Engaged targets at 50m (not our choice. Target frames embedded in ice). Your humble WeaponsMan was firing mostly the Glock (and still struggling to group with it) and Kid mostly a Valmet M62S. Normally we’d only bring one rifle and one pistol to a given range session, in order to maintain focus and maximize training benefit; Sunday we brought an extra handgun (which we’ll explain below).

We also saw, this weekend, bricks of .22 in stock for (ouch)  $70. Not so great ammunition, either: Aquila. But it was the first time in a long time we’ve seen ‘em in stock. After checking on prices online, when we factor shipping in, we’re better off buying it locally.

Of course, buying more .22 means someone is going to have to troubleshoot the old High Standard. Back when we last could get ammo, it was having some going-bang-consistently problems, and it shouldn’t — it’s a pretty simple blowback gun.

The Valmet M62S

We’d cleaned it inadequately last time (boo, hiss). We discovered when the bolt didn’t want to open, but seemed to be welded shut. This is a fault (if a problem caused by poor PM is really a “fault”) of Valmets and Galils (which are Valmet-based) more so than regular AKs, and here’s why:

  1. The Valmet gas piston is not chromed, and therefore is subject to corrosion.
  2. The Valmet gas tube is not a cheap, non-pressure-bearing stamped sheet metal thing that loosely sits around the piston, but a machined part that fits closely.

Valmet_ADm76

(That’s an ad for a very early M76 that still has most of the M62 features, including the machined receiver. Note its similarity to a Galil receiver. All Valmets have the machined gas tube).  

The Valmet designers worked around this a bit by having a sort of sharp-edged scraper in the tube, behind the piston itself. If the phosphated (i.e. Parkerized) finish wears off, this is subject to being seized to the tube by rust. Likewise, the piston itself can rust-seize to the gas block.

Corrective action? Hooked the charging handle on the bench at the range, and gave the butt of the butt stock a good open-palm strike. Opened it up and confirmed it was this type of rust seizure, now cleared; and the gun operated flawlessly for the 90 rounds Kid put through it.

Bear in mind, it never stopped firing — it just wouldn’t open up without a good whack, after sitting for a couple of years. And then, after the whack, it worked just fine.

After all, it’s an AK, just an unusually well-made one.

The Glock

Glock17-G3That file photo’s pretty close to the G17-G3 we’re carrying, although we have the Vickers extended slide release and mag release, and tritium sights. We’re still missing too much with this thing. Arrgggghhh. Time to go to some schools and get some first-class coaching. It’s not the gun. The Glock did its part and, of course, went bang every time with Speer Lawman JHPs. Unfortunately the problem here is beyond gunsmithing — it’s behind the trigger, as it were.

The Beretta M92S

M9-pistolWe have shot Berettas so much it’s not funny. And since we always had one at work, we never bothered to keep one at home. One came up at our local FFL, and the price was reasonable so we scarfed it up. (After all, we’re still finding Beretta mags in old tuff boxes and combat boots). Our basic intention was just to break it in, and so, most of the shooting was done by Kid, who’dd never fired one before (and had just seen one get a workout onscreen in Lone Survivor). Like the Glock, it went bang 100 out of 100 with the Speer JHPs. (We gotta get some more ball for practice. These things are expensive for ventilating targets).

Kid enjoyed himself. What more could we ask for?

The range was followed by lunch at Five Guys. (Urp!) And gun cleaning, from which Kid absented himself… so we set the Valmet aside for him. No Hoppe’s no pop-poppies, around here…

A Short History of Chrome Bores

For some 500 years it’s been known that rifling would impart spin and therefore stabilization to a ball or bullet. Spiral grooves probably evolved from straight grooves only intended to trap powder fouling; by 1500 gunsmiths in Augsburg, Germany, were rifling their arquebuses. This gave rise to an early attempt at gun control, according to W.S. Curtis in Long Range Shooting, An Historical Perspective: 

In the early 16th Century there are references to banning grooved barrels because they were unfair. Students of the duel will recognize this problem arising three hundred years later.

Curtis, 2001. Curtis notes that why rifling was twisted is unknown, and that it may have been incompletely understood. He has quite a few interesting historical references, including one to a philosopher who explained that if you spun the ball fast enough, the demon (who dwelt in gunpowder, which was surely Satan’s own substance) couldn’t stay on and guide your ball astray. (Curtis’s work is worth beginning at the beginning, which is here).

By the mid-19th Century, the Newtonian physics of the rifled bore had been sorted out, the Minié and similar balls made rifled muskets as quick-loading as smoothbores, and the scientific method allowed engineers to test hypotheses systematically by experimentation. So smoothbores were gone for quite a while (they would return in the 20th Century in pursuit of extreme velocities, as in tank guns).

Rifling had several effects beyond greater accuracy. It did decrease muzzle velocity slightly, and it did increase waste heat in the barrel. The first of these was no big deal, and the latter was easily handled, at first, by improved metallurgy. But rifling also helps retain highly corrosive combustion by-products in the bore; and corrosion was extremely damaging to rifling. Pitted rifling itself might not have too much of an effect on accuracy (surprisingly), but the fouling that collected in the pits did. Corrosion also weakened the material of barrels, but most military barrels had such great reserves of strength that this was immaterial, also.

Fouling and pitting have been the bête noire of rifles from 1498 in Augsburg to, frankly, today. A badly pitted barrel can only be restored by relining the barrel, a job for a skilled gunsmith with, at least, first-class measuring tools and a precision lathe with a long bed. Relining has never been accepted, to the best of our knowledge, by any military worldwide.

Chrome Plating is Invented: 1911-1924

One approach has been to use corrosion-resistant materials for barrels, but that has been late in coming (late 20th Century) because it is, of course, metallurgy-dependent. Early in the 20th Century, though, American scientists and engineers developed a new technology — electroplating. George Sargent, of UNH and Cornell, worked with chromium as early as 1911, and Columbia scientists developed a commercially practical process of using electrodes to deposit chromium by 1924. Meanwhile a New Jersey professor worked with a German process.

The two groups of professors formed start-ups, the Chemical Treatment Company and the Chromium Products Corporation. At this point, chrome plating has not been applied to firearms. Electroplating had been used for guns for decades, of course, but that was nickel plating — eye-pleasing, but soft and prone to flaking, not suitable for bores, and not remotely as corrosion-resistant as chromium.

(This article is rather long, so it is continued after the #More link below. We next take up the application of this process to rifle bores).

Continue reading

Closed vs. Open Bolt technology

Screenshot 2014-01-06 00.56.15It’s generally understood that weapons that fire from an open bolt are less accurate than those that fire from a closed bolt. It’s certainly logical that both the weight of the moving bolt, plus the inevitably longer locktime, will increase dispersion. An interesting controlled experiment the US Army conducted in 1978 confirmed the existence of, and tried to quantify, this increase in dispersion. Additional findings were that:

  • Not just the dispersion, but also the precision of the shots suffered. That is to say, not only their separation one from the next in the same group, but their separation from the intended point of aim.
  • Comparing prone unsupported to the less accurate and consistent offhand position, the penalty for using an open bolt was greater in the offhand (this might be predicted logically).
  • Right-handed shooters were consistently off target to the right, and this increased when firing from an open bolt. Lefties erred in the opposite direction.

Unfortunately the only usable data come from the dry-firing tests, in which a laser and receptor were used. This methodology could not be validated by live-fire testing for an interesting reason: the innate accuracy of the weapon they used, the XM19 SPIW, was so poor.

For the purpose of the test they had a single XM19 and a quantity of XM645 flechette ammunition. The test weapon was Serial Number 6 and was lent to the Ballistics Research Laboratory by the manufacturer, Aircraft Armaments Incorporated of Maryland.

THE XM19 was AAI’s entrant in the Special Purpose Individual Weapon contest in the 1960s, and the follow-on Future Rifle Program of the 1970s. It fired flechettes at a very high cyclic rate and was intended to mate with a grenade launcher (the M203 was an outgrowth of the first stage AAI’s GL development; a second-stage repeating launcher was not a success). It had extreme reliability problems; while then-current service weapons, like the M14 and M16, could fire thousands of rounds without a stoppage, the XM19 never managed more than dozens. (In a profile of AAI founder/designer Win Barr for Small Arms Review, George Kontis wrote that bad single-shot accuracy at range was what killed the AAI flechette rifle).

The XM19 was also badly designed ergonomically, awkward, overweight, and muzzle-heavy even without the grenade launcher (which was not installed during the 1978 tests). Why this test was not done with a more conventional weapon is unclear. It may have simply been opportunistic, in that both open- and closed-bolt lockwork for the XM19 was readily at hand.

These facts suggest a follow-on experiment. It would be worthwhile to repeat the test but with a more modern alternative. For example, if you got 20 marksmen to fire 10-shot groups each with an AR clone rigged to fire from open and closed bolt.

That’s a problem with the ATF, which defines any open-bolt semiauto as a machine gun, no matter how robust the disconnector is. But the work-around is to use a lower with no magazine well at all. A single-shot weapon can’t be a machine gun, no matter how intently the ATF tries to find a technical violation to fry somebody for.

The original, primary-source document. Technical Memorandum 2-79, Aiming Point Displacement from Firing a Rifle from the Open-Bolt Position by Dominick J. Giordano, is available:

  1. From DTIC:  Abstract.  Full document (.pdf)  (Our apologies for the poor resolution of the photos, DTIC appears to pull these from microfiche, which yields an equivalent depth of 1-bit per pixel).
  2. From right here at WeaponsMan.com:  ADA068215 .pdf

7 8 American “Firsts” from the M14 Rifle

This M1A is a civilian M14, a rifle whose development was deeper than it looks at a glance.

This M1A is a civilian-legal clone of the M14, a rifle whose development was deeper than it looks at a glance.

By the time we were on the ground and familiar enough with military weapons and the employment of same, the M14 Rifle was long obsolete. It persisted in some specialty uses: as the M21 Sniper System, an accurized National Match M14 with a ART II scope (or awkward PVS-2 image-intensifying night sight) was our primary sniper arm, at least until the development of the M24 Sniper Weapons System. The M24 had the M21 beat on everything but second-shot capability: it was more accurate, more durable, more dependable, and lighter. But when all we had was the M21, we thought it was pretty good. Other than that, the M14 was used as a makeweight in training courses, and as a way to give opposing forces a dissimilar weapon in force-on-force training with blanks.

It was easy to develop some contempt for the weapon that was even more short-lived than the .30-40 Krag, at least as a first-line service rifle. The reason we used them for opfor weapons and rebuilt them into barely adequate sniper guns was that we had them, and so the incremental cost was zero. Indeed, it would have cost the Army money to get rid of them; with full-auto capability, at least in theory, they couldn’t be sold to civilians, and no army in the world wanted them. So they became an extra weight to carry at SFQC instead of an M16, and were issued to “aggressor” role-players in Ranger School, along with obsolete khaki uniforms. After all, the M14 was a very mild refresh of the M1 Garand, a perfectly serviceable weapon, but one destined to be swept away by history. It was kind of like Raymond Loewy’s restyling of a 1950s Studebaker into the 1960s Hawk — too little, too late; it was still the old model underneath, and by 1964 you could get a modern-all-through Riviera or T-Bird, or its gun equivalent, an Armalite.

After all, the M14 was a 12-year government RDT&E circus that meant to do no more than give the old standby M1 a new NATO cartridge, a box magazine, and an improved gas system, and after 12 years, that’s all it really did.

But the M14 deserves a little more respect that that, we learned from Random Shots: Episodes in the Life of a Weapons Designer by Roy Rayle. The M14 might have been a kissin’ cousin of the M1 with some 29 interchangeable parts, but it broke new ground, and racked up an impressive list of firsts — some of them American firsts, and some worldwide.

  • 1. Chrome bore: While Russia and Japan were doing this as far back as WWII, the M14 was the first American service rifle to have the durability and maintainability benefit of a chrome-plated bore. The T44 prototypes that edged out the FN-FAL for the contract didn’t have this but the contract given to Springfield Arsenal in March, 1958 for a pilot run of 15,600 rifles specified a chrome bore. All subsequent M14s had it, too.
  • 2. Hammer-Forged Barrel: this German innovation, in which a barrel is compressed by automatic hammers over a mandrel imprinted with a negative image of the rifling and chamber, was first used in the USA by the aerospace and defense firm TRW (Thompson Ramo Wooldridge), which bid very low to secure a contract for M14s, and then applied the best aerospace, automotive, and gun-making technology available worldwide, to make a profit at that low price point. (Only TRW barrels were hammer-forged or as TRW called it, hammer-swaged).
  • 3. Precision Castings: The complicated flash suppressor of the M14, for example, was machined from a precision casting. The technology used varied from manufacturert to manufacturer (M14s were made by Springfield Armory, Winchester, Harrington & Richardson, and TRW).
  • 4. Synthetic Stocks: While the M16 is what people think of when they think of synthetic stocks, the Army used them as early as World War II on the BAR and M1919A6 (there was also a Garand stock, that was designed but never made in quantity). But the M14 was designed from the beginning to have a synthetic stock (the initial guns had wooden stocks and fiberglass handguards. While the WWII stocks were designed to be stronger than wood for the same weight, the designers’ objective on the M14 was to make a stock as strong as wood but much lighter. The M14 has the curious distinction, then, of being the first US service rifle designed to wear a synthetic stock, as well as being the last US service rifle to wear a wooden stock.
  • 5: Stock full of Cleaning Gear: The M14 stock was hollowed out, and the buttplate contained a trap door, for the storage of cleaning gear. The trap was designed exactly to fit specific M14 cleaning and maintenance equipment. This feature was common on other nations’ rifles, but the previous US service rifles (M1903 and M1) did not have it. Oops. As you can see from the comments, we laid an egg on this one.
  • 6: Sights in Meters: This too was an innovation not present in the protoypes, but applied to the 15,600 pilot program guns. One small change order for a production plant, one massive tectonic shift for the training base and culture.
  • 7: Advanced Mass Production Technology: H&R basically followed Springfield Armory’s plant layout and process sheets, but both Winchester and TRW used advanced technology to revolutionize the production of M14s. Winchester used two machines called Gorton lateral transfer machines to produce the receiver. Instead of passing the part from one single-set-up, single-operation machine to the next (mostly horizontal milling machines, but also broaches, etc.) these two machines performed 32 different cuts on the receivers. Winchester also had a 16-station duplicating inletter producing 16 stocks at a time, and a bank of eight six-spindle barrel-drilling machines. TRW rejected Springfield’s approach and processes, and essentially re-did the production engineering ab initio. They used advanced machinery for 11 different parts. Bolts went two-at-a-time through a Krueger lateral transfer machine that performed 30 operations. This machine replaced 15 separate machines and setups. Receivers were put on a Colonial continuous-chain broaching machine, which shaped each receiver at 15 different stations. The high-tech paid off, with the TRW guns in particular selling to the government for a little more than half what it cost Springfield to produce the same firearm. Contractors for Springfield Armory originally calculated the straight-up cost (no profit) of the M14 as likely to be 110% of the M1’s $75. Winchester and H&R sold their M14s for about $116, it cost Springfield $150 to make one, but TRW’s contracts came in with unit prices in the $70s and $80s.
  • 8: Electromagnetic Comparison Inspection: A problem with H&R receivers and bolts was traced to a bad batch of steel. But H&R hadn’t recorded which parts were made from which batch, and a large number of parts couldn’t, in good conscience, be assembled into guns without some kind of inspection. Rayle (p. 85):

The technique finally adopted for this purpose was an electromagnetic one. It had long been known that the magnetic properties of steel vary with the composition, heat treatment and metallurgical composition of the steel. A thorough study by the metallurgists at Springfield Armory, aided by metallurgists at Watertown Arsenal, refined the techniques of operation to establish a workable procedure.

A reference receiver known to be good was placed in the magnetic field of one coil, and the unknown receiver in the field of another coil. A circuit was arrange such that if both receivers were the same, no voltage output would be received, but if the magnetic properties were different, a voltage would be obtained roughly proportional to the difference in magnetic properties.

Sounds complicated, this device (which came to be labeled a Magnetic Analysis Comparator). The cut-off score was plus or minus 40 on the comparator. How did they know they were getting valid data? They tested the test.

A sufficient number of carefully prepared sample specimens were checked out to ensure the reliability of this convenient inspection technique.

A similar magnetic analysis comparator technique is taught today to nondestructive inspection technicians, but in 1960 it was one of the many “firsts” of the M14 program.

Summing up

Some of these eight seven advances were more revolutionary than others. Empires do not rise and fall on a buttstock cleaning-kit compartment. And the productivity that came from analog high production machining centers was a short-lived stage of technological development. In 1960, even visionaries couldn’t foresee digital readouts, CNC machining centers, and robotics. 

But these innovations large and small show that neither Army Ordnance nor industry was napping during the M14’s long gestation. The rifle had some teething troubles (the above-mentioned bolt and receiver problem involved them going kB!, for instance), but the rifle that had one of the shortest times in service as the standard infantry individual weapon has gone on to keep serving in specialist roles, mostly as a designated marksman’s rifle, today.

Thousands of stored M14s were rebuilt into the M14 Enhanced Battle Rifle in the mid-oughts. So the old warhorse outlived its wooden stocks, and even its plastic ones, and is now rocking an aluminum chassis. Kind of makes you want one, doesn’t it?

One, thousand, two, thousand… six thousand, THWACK!

Operation Enduring FreedomOf course, from the point of view of the Taliban, nobody knew anyone was counting down. It was just thwack! out of the blue, and their commander was instantly among 72 virgins, clean young boys, or, possibly, goats. (Hey, we’re non-judgmental about Taliban lifestyle choices around here).

His fellow Talibs didn’t know what or who killed him, or why. But his death was an instant, undeniable, and demoralizing fact.

The men who knew the answers were lying prone a mile and three-quarters away. They were Australian snipers from D Coy 2 Cdo, and they’d just shot him with a Barrett .50 caliber sniper rifle. Chris Masters in the Telegraph (AU):

Two marksmen using Barrett M82A1 50 calibre rifles simultaneously fired. The bullets were six seconds in the air. One killed the Taliban commander. It is not known for certain which sniper fired the fatal shot.

While there have been no triumphant press releases, in the tight global Special Forces sniper community the shot is much discussed, because it seems certain to be a world record.

As the bullet yawed through the thin air on a windless morning, GPS aids measured the distance at 2815m. That amounts to 2 1/2 times the length of the Sydney Harbour Bridge. The targeted Taliban would not have heard the gunfire.

The previous world record achieved by British Corporal Craig Harrison occurred also in Helmand in November 2009. Firing from a distance of 2475m, Harrison killed two Taliban.

While British, American and Canadian sharpshooters are often celebrated the Australian Defence Force says nothing. When I sought to check this story I was politely told I could not be assisted. Fair enough. We are not talking about an Olympic event. An expert I did prise a few words from said that shooting at that distance beyond the weapons capability calls for luck, but it had still taken skill.

That’s a reasonable assessment of the shot. Even a smith-tuned Barrett with painstakingly crafted handloads isn’t going to shoot minute-of-hadji at a mile plus. Not consistently, anyway. A rack-grade Barrett with MG ammo is already off a man-sized target half the time at 1000m. Hence the redundant shooters.

This is not only the longest shot we’ve heard of, it’s the longest Barrett shot by far. (Most of the really long shots have been with bolt guns).

Of course, we don’t know how many unsuccessful shots have been taken at this range. This is really way out over the ragged edge of what is routine for elite snipers; it’s barely possible, with a little luck.

When Masters says, “The targeted Taliban would not have heard the gunfire,” he’s probably referring to the arrival of the lethal projectile well ahead of its trailing sonic shockwave or the atmospheric-limited muzzle blast, but depending on the atmospherics, there are good odds the surviving Talibs didn’t hear the gunshot at all. (It would reach them, if it did, several seconds after the sickening thwack! that announced their leader’s demise).

This kind of sniping is extremely stressful and strain-inducing to the element under fire. The conventional military countertactics don’t work when your assailant is “out there” somewhere. Your element’s deaths seem fruitless, pointless, and they go unavenged. And the point of the sniping is, not merely to slay enemy leaders but to sow just this sort of psychological corrosion.

Only accurate, effective sniping produces the full effect in the enemy’s mind.

The Commandos are among the last conventional Australians to redeploy to their home island/continent, but any relief the Taliban feel needs to be somewhat tempered — the OZ SOF are planning to stick around for four or so more years. And any one of the Talibs could be six seconds — or less — from thwack!

5 Reasons for the AK’s Legendary Reliability

AK-47The Avtomat Kalashnikova obrazets 1974g and its successors have an enviable reputation for reliability, especially under adverse conditions. There are a number of reasons for this, and we’ll go into them in some depth here. First, though, let’s say what is not a cause:

  • It’s not because of blind luck.
  • It’s not because the weapon is orders of magnitude better than its worldwide competitors. Indeed, by the end of WWII a very high standard of reliability had come to be expected, and weapons that did not meet this standard were mercilessly eliminated, like the Johnson M1941 and the Tokarev SVT.
  • Mikhail KalashikovIt’s not because Kalashnikov the man had genius that was lacking in other men. His competitors in the field, from Browning, to the Mauser-werke engineers of the 1940s to Stoner, were certainly men of genius as well. (Heck, so were Tokarev and Johnson). He’d have been the first to tell you he was just a thinking engineer.
  • It’s not because of breakthroughs. Almost every feature of the AK is recycled from somewhere else. What Kalashnikov did was synthesize them in a new way.

The Kalashnikov rifle is not, in fact, a universally superior design. Compared to its worldwide competitors (the FN SAFN and FAL, the CETME and G3, the M14 and M16 series, to name the most important), it is less accurate, less flexible/adaptable, and less ergonomic than every other. It offers less practical range than any other; and at the other extreme of range, it is the worst bayonet handle. It weighs more than some, has the heaviest magazines by far, and has an inferior weight-to-firepower ratio to most. It is inaccurate from the shoulder in full-automatic fire, yet it is designed to be fired, preferentially, on full automatic.

The strengths of the AK have overcome these deficiencies to make it incredibly common worldwide. Those strengths, compared to its competitors, include a somewhat lighter weight of ammunition, a larger standard magazine, great simplicity of operation and ease of manufacture, and that vaunted reliability, perhaps its most salient characteristic.

Design features of the AK which contribute to its reliability include:

1. Simplicity

The AK is almost as simple as a hammer. It is simple to build and manufacture (we’ll go into some specifics below). It uses no space-age materials, not even any aeronautical technology, just 19th-Century steel and iron and wood. (Much later, Kalashnikovs would have composite magazines and composite furniture. The US put composite stocks on BARs by 1944, and had them ready for the M1 and M14 in the 1950s, but an AK would not have a composite stock in its home nation for another forty years). There is no advanced machinery needed to produce an AK — indeed, one can be built (and they have been built) with hand tools and no precision measuring equipment, not even a micrometer. The rifle itself has no parts that cannot be filed, ground or machined from steel, or hammered from sheet metal, or riveted or welded from parts made this way. Most auto repair shops have the tools needed to build an AK, apart from rifling the barrel; the necessary materials are in the same shop’s scrap pile.

The AK’s operating system is simple and proven, a long-stroke gas piston system and a rotating bolt. Unlike the dainty bolt of the AR system (lifted itself from the M1941 Johnson) with its 7 precision locking lugs (and one false lug on the extractor), the AK bolt has two locking lugs, oversized, overstrong, and remarkably tolerant of undersized contact patches with the locking recesses of the trunnion. (Factory AKs have wide disparities here, especially those made by some of the more slipshod non-Russian, non-Chinese factories. The guns all seem to headspace correctly, operate normally, and fire reliably).

The AK does have one part that is a highly complex weldment: the magazine. The magazine and the feed path in general is very simple, straightforward, and repeatable, which is why the mag clearly got a lot of engineering hours. Gun designer David Findlay, who’s worked at Remington, Marlin, H&R 1871, and Smith & Wesson, says**:

Feed-system design, though, is one of the most important aspects of any weapons performance. A great deal of testing must be done to ensure good performance. Small variations and subtleties in magazine dimensions can have enormous impact on gun reliability and function.

Findlay wrote these words in explaining the engineering of the feed path of the Thompson Submachine Gun, but they’re generally applicable, and go a long way to explaining why Mikhail Kalashnikov lavished so much care on the magazine design. The fact that the receiver of the AK has received many modifications, but that the only change to the magazine is in reinforcing ribs and later magazine-body materials seems to hint he got it right.

An old engineer’s quip is that the designer’s objective is to “simplicate and add lightness.” (This has been attributed, among others, to automotive engineer Colin Chapman and aerospace engineer Burt Rutan). Mikhail Kalashnikov started off by “simplicating” most of the potential for trouble out of his design. (He didn’t make “adding lightness” a priority).

2. Environmental protection

Every designer has long known that foreign matter — mud, dust, and what have you — are the bitter enemies of reliable function in the short term, and that corrosion, rust, is the long-term destroyer of gun reliability. If you examine an AK you will see that it’s hard for foreign matter to intrude into, say, a dropped rifle. The safety, modeled loosely on that of the Remington Model 8 (a Browning design), does double duty in sealing the gap between the receiver and the nonstructural receiver cover. In operation, the charging handle, which is part of the bolt carrier, reciprocates in the open slot that the safety/selector seals shut. That seal and the lack of other large entrees into the receiver keep the interior clean.

Unlike Browning or Stoner, Kalashnikov was limited by the Soviet industrial base; he couldn’t call out exotic materials or sophisticated protective treatments, so early AKs were all steel and rust blued, an attractive finish that was weak at preventing corrosion. Some critical parts, though, notably the gas port area, the gas piston, and the bore, received hard chrome plating, and the weapon is designed in such a way that rust or pitting on other parts just does not matter in terms of reliable function or accuracy. It’s not unusual to find AKs in the field with all kinds of surface rust and pitting on their exteriors, only to find that the vitals, protected by chrome plating, have held up, and the guns still shoot within the modest (and sufficient) standards of a new AK.

3. Lack of small, dainty (and fragile) parts

A field-stripped AK contains nothing you’ll need to grope for if you drop it in tall grass (or mud, or a stream) in the dark. The pieces are big and robust, deliberately so, and this philosophy extends to the internals.

heartbreak ridge AK47 2

Nothin’ dainty about it.

The story of the development of any weapon you care to name involves interesting (and sometimes distressing) breakages. The FN, for example, was prone to firing-pin failures (the answer, which took the experts of three countries to fix, was to reduce the hardness of the part, as measured on the Rockwell C scale, and to shot-peen its surfaces: problem solved). The very first AR-10 tested by the US government had a bullet emerge from the side of the barrel in testing, not exactly a confidence-builder. (They gave up on an AL alloy barrel with a steel liner, then, which neutralized the gun’s weight advantage over the extant M14). Indeed, the AR-10 had terrible problems well into its development and production, and the Portuguese were still solving problems with it during their colonial wars in the 1970s. Many of those same problems, and a set of new ones, struck during development and production of the M16. The AK presumably had problems with these, but because the information was closely held at the time, archives have not fully opened, and most of the principals passed on without leaving technical memoirs, we know about only a few of them (for example, the failure of the first model stamped receivers, which caused a change to a machined-from-billet receiver).

The internals, though, seem to have been robust from the very beginning. Kalashnikov’s point of departure was the Garand trigger group, which itself borrowed from Browning. (Stoner would choose that same point of departure). This is part of the brilliance of the design: he wasn’t inventing for the sheer joy of inventing, but to make something that worked. That means, where he didn’t have a way of doing it better than someone else, he borrowed happily.

Borrowing aside, the Kalashnikov’s departures from Garand practice (apart from those required to render the weapon selective-fire, and to improve the Garand’s sub-optimal safety) showed a lot of interest in making things sturdier. The hammer spring, for instance, is made of two wires coiled together, giving some small redundancy; it also does double-duty in the AK as the trigger return spring.

4. Minimal use of tight tolerances

There are some parts of a gun that absolutely must fight tightly to ensure accurate, safe, and yes, reliable operation. On the AK, almost all of those are permanently assembled at the factory (the barrel into the trunnion, for example). The trigger mechanism is designed with a lot of slop and play in it, which is why AKs have that typically very long, smooth trigger pull with a surprise let-off (SKSes are similar), but it isn’t that way to manage the trigger pull: it’s there so the mechanism will be positive and safe the first time and the 1,000,000th time.

The only moving parts with truly tight tolerances are the fit of the bolt lugs into the trunnion, which affects headspace. For safety and accuracy headspace has to be right on. But the non-bearing surfaces in the trunnion are opened up enough that dust and dirt has somewhere to pack into, other than interfere with the tight fight of bolt to trunnion. John Garand considered the wise use of tolerances key to the legendary reliability of the M1*. Like the AK, its only critical tolerances in the operating mechanism come from the interface of the lugs of the rotating bolt with the mating recesses of the receiver. 

5. Use of very loose tolerances everywhere else

Garand deliberately eschewed the use of a bolt carrier in place of an operating rod. He considered the competing bolt carrier and tipping bolt design (as used in Tokarev, Simonov and FN rifles) more troublesome both in production and in service because they had more critical tolerances. While the AK uses a bolt carrier, its fit to the bolt and receiver is if anything even less critical and looser than Garand’s op-rod.

What Rayle (and Garand) thought of as an innate flaw in bolt-carrier vs, op-rod systems, the need for precision tolerances both on the locking/headspacing feature of the bolt and its receiver, and also on the interface of the bolt with the bolt carrier, turns out to be an innate flaw in the Browning (Tokarev, Simonov, Saive, Vervier, etc). tipping bolt. The AK’s bolt can interface with its carrier just as loosely as the M1s does with its operating rod, with no harm to the functioning of the rifle.

This is not to say that nothing on the AK is manufactured with precision. (That would be the STEN). The beauty of the AK, from an engineering design viewpoint, is that nothing is manufactured with unnecessary precision.

To Sum Up

aklgcolcopyThese things, taken together, suggest that the AK is narrowcast at its original role as a submachine gun replacement for the semi-literate peasant conscript army of a nation lacking depth in precision manufacturing. It was the perfect gun for the Red Army in World War II, even if it came a little too late. It was also, therefore, the perfect gun for the continuation Soviet Army.

Unlike the service rifles of the USA or Germany, or the first-generation battle rifles of the West in the 1950s, the AK was manufactured without an excess of precision which limited its adaptability as, say, a sniper rifle. (The AK’s then-unique use of an intermediate cartridge also did this). But it suited Soviet doctrine of mass attacks and mass fires well. Unlike the NATO rifleman, the Soviet soldier, although instructed in semiautomatic fire on ranges, was also extensively drilled in live-fire obstacle courses, and was expected to run them firing on full-automatic, from the hip. He was the heir of the submachine-gun battalions of the Battle of Berlin, and planned to fight the same way, as mechanized infantry guarding the flanks and securing the obstacle-ridden forests and towns to enable the great tank attack. Hence, the first click off safety on an AK is full-auto, contrary to every successful NATO selective-fire rifle.

The same adaptations, design decisions, and production practicality that made the AK a perfect replacement for Ivan’s retired PPSh submachine guns, made the AK a perfect weapon for terrorist groups, “national liberation” movements, and under-resourced armies of newly free colonies worldwide.

Like the Mauser before it, the AK is a universal gun. And like the Mauser, the AK will be with us until something better supplants it. And “better,” in this case, will be defined by history and by nations, not necessarily by gun experts.

 

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* John Garand’s comments come from Rayle, Roy E. Random Shots: Episodes in the Life of a Weapons Designer. 

** Findlay, David S. Firearm Anatomy: Book I: The Thompson M1A1 Submachine Gun. p. 76. San Bernardino, CA, 2013: Findlay, David S.

A few Christmas gift ideas from the past

Just because these ads are old, doesn’t mean any one of them is a bad idea. The British, whose chains rest lightly on their shoulders, don’t get it; an excited Chris Pleasance in the Daily Mail seems Shocked!, Shocked! that we barbarians in the Colonies once gave guns as Christmas gifts, but reassures him/her/it-self that the ads are “outdated.”

Hmm. These ads do date from the 1950s and 1960s, but nobody better tell Chris that more guns are being given and received under this year’s Christmas tree than were when the ads ran. And kids will still look like this happy guy when they open the long rectangular package:

winchester christmas

Once, a kid reacted much like that to find his first .22 — a Winchester, as it happens — under the tree. His Dad bought it for him, despite Dad not caring much for guns; because it was what the kid wanted. He was an incipient WeaponsMan, after all.

Thanks, Dad. The Winchester is still in a place of pride alongside guns that are insured for orders of magnitude more, but are worth orders of magnitude less.

As the labels on the images show, but the ingrate Pleasance and his tabloid don’t actually say, the ads came from Retronaut.com, an interesting source of midcentury style. They were posted on Retronaut a couple of years ago.

Along with Winchester, we have Remington, Browning, and High Standard as well. They’re over the jump to keep the front page lean — click “more” to see them, or click on through to the Daily Mail to see them with mildly appalled British condescension, or to Retronaut to find them amid the cars with jaunty tailfins and men in snappy hats.

Continue reading

Another Official Nomenclature Cross-Reference List

Here again the Army is trying to map the actual nomenclature used for a weapon to the Army’s preferred terms. We put up the one for the M16 series weapons back in November. Let’s play a little game: can you guess the weapon?

The Army’s terms, though, are fairly useless. They  are often generic, and don’t describe the use or purpose of a “helical compression spring” (coil spring, used several places in this weapon) or “socket head cap screw” (in this weapon, the muzzle brake screw)). The Army also officially calls some coil springs “helical compression springs” and other coil springs “compression helical springs.”

Nomenclature Cross-Reference List

Common Name Official Nomenclature
Accelerator Rifle accelerator
Adjustment turret cap Dust protective cap
Anti-reflective device Optical eyeshield
Barrel Rifle barrel
Base plate Magazine floor plate
Battery bumper Nonmetallic bumper
Bipod detent
 Headed straight pin
Bipod locking pin Quick release pin
Bipod pin Spring pin
Bipod spring Helical compression spring
Bolt Breech bolt
Bolt keeper Lock washer
Bolt latch Lock-release lever
Bolt latch spring Compression helical spring
Cam pin assembly Machine breechlock cam
Cocking lever pin Bolt carrier pin
Extension stop pin Bolt carrier pin
Extractor Cartridge extractor
Extractor plunger Cartridge extractor
Eyepiece lens cover Lens cap
Impact barrel bumper Nonmetallic bumper
Knurled lock ring Knurled plain nut
Laser filter unit Telescope light filter
Magazine catch pin Spring pin
Magazine follower Cartridge follower
Midlock pin Quick release pin
Muzzle brake screw Socket head cap screw
Muzzle brake shim Shim set
Muzzle brake washer Flat washer
Pistol grip Rifle grip
Rear lock pin Quick release pin
Rear sight scale Rear slide assembly
Scope ring assembly Telescope mount
Scope ring bolt Machine bolt
Scope ring screw Machine screw
Sear pin Bolt carrier pin
Telescope Optic mount system
Windage knob pin Spring pin
Yoke mount washer Lock washer

These things never fail to amuse us. The Army’s insistence on obsolete, pedantic, and nondescriptive language is reminiscent of the Academie Française standing boldly athwart the modernization of the French language — or trying to.

Culture moves on, and pedants can’t stop it, whether they’re wearing uniforms or mortarboards.

The weapon? The Barrett .50 Semiautomatic Rifle. This Nomenclature Cross-Reference List is from  TM9-1005-239-23&P: Technical Manual, Unit and Direct Support Maintenance Manual (Including Repair Parts and Special Tools List) for Long Range Sniper Rifle, M107 / USMC Special Application Scoped Rifle (SASR).

(Extra irony points for the Army and Marines insisting on different terminology for the same firearm).

Foreign & Obsolete Weapons Training

SF NCOs conduct mechanical training on AK rifles for troops of the Malian Army.

SF NCOs conduct mechanical training on AK rifles for troops of the Malian Army.

When we attended what was then Light Weapons School (then Phase II of a Weapons Man’s SFQC), the stress was on mastering the mechanical operation and employment of foreign and obsolete small arms. Given the environmental changes of the last thirty years, the current course has lots more shooting and teaching-of-shooting (big improvement), lots more base defense and tactics, includes heavy weapons training including weapons that were then-novel and not included in a Heavy Weapons NCO’s training (like ATGMs and MANPADs) and is nearly twice as long. (In 2014, it becomes fully twice as long).

One of the things that’s been cut to make room for the course improvements, is a lot of the foreign and obsolete weapons training. We understand why, but believe that foreign and obsolete weapons training is good for not only SF but also for other members of combat units.

In World War II, paratroopers were taught to manipulate the enemy’s small arms, and that seems like a no-brainer. For SF, who are likely to operate with irregulars armed in part via battlefield recovery, this is obviously important, too.

Foreign weapons mechanical training has the following benefits:

  1. It builds confidence in US weapons, which are equal to or better than their world competitors at this time.
  2. It enables troops to use Allied and enemy weapons should they be required to in combat.
  3. It gives troops a chance to see foreign weapons at all ranges, including up close, and at all angles, increasing their ability to identify foreign equipment from photographic or personal reconnaissance.
  4. It demystifies foreign, especially enemy, forces to see and handle their weaponry.
  5. It is mentally engaging and physically confidence-inspiring.

Mechanical training is good, but to take it to the next level, the combat unit should consider foreign weapons firing training. This requires more instructors, armorer-certified weapons, ranges, and ammunition.

Foreign weapons range firing does all the same things that mechanical training does, and adds benefits to each. For example, attempting to zero and fire an AK for record makes one truly appreciative of the sights and inherent accuracy in the M16 and M4 series of weapons.

Live fire training does additional things besides.

  1. Accustoms the students to the sound of enemy weapons. Most enemy weapons have distinct reports that experienced combat troops learn to recognize. Firing foreign weapons on the range accelerates this learning so that it need not be done under fire and at great risk. Along with the individual sound of gunshots, most auto weapons have distinct rates of fire. This benefit is amplified if the troops can hear the weapon from distinct angles safely, particularly from downrange (i.e., in a target-butt trench).
  2. Accustoms the students to the sight of enemy weapons. (Dust, muzzle flash by day and night, distinct tracer appearance, etc).
  3. Prepares the students much better to fire a battlefield-recovered weapon, should that be necessary.

Obsolete Weapons training has fewer distinct benefits, but is still helpful.

  1. It helps them position current US weapons longitudinally in weapons and technological history.
  2. If enough versions of weapons are available, it can prepare students for an encounter with novel weapons, by giving them a wide range of operating principles and maintenance procedures to consider.
  3. It does help in those environments where obsolete weapons are likely to turn up — a set which includes many war zones. For example, Czech ZB-26 light machine guns, Egyptian “Port Said” copies of the Carl Gustav M45B submachine gun, and long-obsolete Russian DP-series machine guns were widely encountered in the early days in Afghanistan. Long-outdated M1 Carbines still turn up worldwide, as do STEN guns; Syrian rebels found a cache of German MP-44s.
Marine fires a PKM light machine gun in training provided by International Police Supply, a contractor.

Marine fires a PKM light machine gun in training provided by International Police Supply, a contractor.

While the US Army once had the capability to conduct this type of training, it destroyed its in-house capability with multiplying and metastasizing bureaucratic regulations. At one time, to fire a foreign weapon, it needed to be “certified” by a specific office at Aberdeen Proving Ground. The office granted a one-year certification that took over a year for them to issue, so that you needed to have three of any given weapon in order to have one available to shoot regularly. In practice, any gunsmith or armorer with his ordinary tools and a set of headspace gages should be able to pass judgment on the safety of a foreign or obsolete gun.

As a result of the Army’s mismanaging its own capability to provide this sort of instruction, a niche has opened up for contract providers. The problem is, of course, that armed forces units seldom have the budget to engage such a contract provider.