5 Reasons for the AK’s Legendary Reliability
From WeaponsMan: The 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.
It’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:
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.
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
These 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.