The AK-47 has the slanted gas block, the AK-74, the upright one. Unless, of course, a manufacturer simply uses AK-74 gas blocks on rifles in 7.62x39.
MIKHAIL KALASHNIKOV WAS A GENIUS. However, there are different kinds of geniuses. If you haven’t had the opportunity to hang around with people at that level, you might not know that they can be remarkably different. In the classical music field, Mozart was a genius. However, his differed from earlier geniuses in that what he did was take the existing music and combine it with new combinations, patterns, and forms. A newer example would be Chuck Berry, Eric Clapton, and Eddie Van Halen. What Chuck Berry did with the guitar was new, while Eric Clapton and Eddie Van Halen produced music at a new level of virtuosity. Their groundbreaking efforts were in virtuosity.
The AK-47 has the slanted gas block, the AK-74, the upright one. Unless, of course, a manufacturer simply uses AK-74 gas blocks on rifles in 7.62x39.
In the firearms field, John Moses Browning, John Garand and Mikhail Kalashnikov are similarly positioned. Everything Browning did was actually new. Everything. From self-loading pistols and shotguns, rifles and machine guns, even calibers, what he did was new and groundbreaking. When Browning invented a self-loading shotgun that worked (the A-5), he not only patented the operating principle, but three different ways to retract the bolt to charge the chamber. Now that’s innovation and originality. John Garand did what no one else had managed to do previously — he developed a self-loading rifle in a full-power military caliber, one that met the overly ambitious and unrealistic requirements of the U.S. military. What Kalashnikov did was take several existing designs and put them into a single rifle.
I can hear the screams now: “Heresy! The AK is unique, perfect, indestructible and a product of genius. Burn the heretic!” The genius part I can agree with, the rest, well, you’ve been drinking deeply the AK Kool-Aid, comrade.
Ah, the finest socialist manufacturing quality standards. This 1983-made Romanian AK came complete with machining chip still attached.
Kalashnikov borrowed the safety/selector from the Remington Model 8.
A proper aperture sight is close to the eye, allowing the eye to work naturally.
The Soviet request for a new rifle did not include accuracy beyond what was needed. So while the American M14 could be rebuilt as a sniper rifle, no AK could be.
The AK two-stage hammer/trigger design comes straight from John Browning. Here we see it in an M14.
The middle of the receiver has a reinforcing pillar, a tube held in place with a long rivet.
What are the parts that Kalashnikov incorporated into the AK? First, the piston and carrier design comes right out of the M1 Garand. The long rod, driven for a short distance by gasses before it vents to the exterior, is all Garand. As is the angled cam slot that actuates one locking lug of the bolt. (Winchester also appropriated that for use in the M1 Carbine. Ditto the U.S. Army Ordnance bureau when they screwed up the M14. Good designs never fail to be copied, and Ruger copied it again in the 1970s for the Mini-14.) The AK bolt is also a Garand style. It features opposing locking lugs, with one of them used as the lever point of the carrier cam slot, then traveling with the carrier for the length of the stroke. The double-hook trigger mechanism is of the Garand, but John Garand borrowed it from John Browning. The double-hook trigger mechanism dates back to the Auto-5 shotgun and the Remington Model 8 rifle. The safety also comes right from the Remington Model 8, first made in 1906. The pivoting lever that both blocks the trigger mechanism and the bolt, and acts as a dust cover, comes from the Remington Model 8. The sheet metal construction of the receiver (the first models were made that way) comes from the various iterations of the German rifles, which from the Mkb42 to Stg-45 were made with stampings. While Soviet designers would have been familiar with sheet metal pressings as a construction method from their own Sudaev PPS-43, it is significant to note that going from that open-bolt blowback mechanism to stampings with steel load-bearing internals happened only after the Soviets were exposed to the MP-43/Stg-44 rifles. Also, the curved, double-stack magazine, feeding from both sides came from the Stg.
Pistol grips are not new, as every second generation submachine gun has one. Also, the sights are the standard European rifle/submachine gun sights, a post out front and a notch in a range adjustable rear forward of the action.
Given the simplicity of the design, hand-building new AKs, or upgrading them, is easy.
The cammed locking lug path is a direct descendant of the M1 Garand and has been used many times since.
The piston, driven by gasses, attached to the operating rod, is from the Garand. Here is an AK, next to the “refined” version from an M14.
By putting the gas system above the barrel, Kalashnikov made his life so much easier.
You have to wonder what the arsenal workmen were thinking: perfectly good, capitalist-shooting rifles, being scrapped, and the scrap sold to capitalists. What is the world coming to?
To make new receivers, you only need a simple, multi-ton press. Thank you, Mikhail.
This scrapped and cut-apart receiver shows the bolt guide rail and ejector.
What made Kalashnikov a genius was that he put all these together, and used the M-43 medium cartridge instead of the previous military imperative of full power. One aspect of the AK-47 where Mikhail did innovate was the gas system — as in its location. He put the gas system above the barrel. All other attempts to design a self-loading rifle had placed the operating system below the barrel. By going above the barrel, Kalashnikov solved a number of problems. First, heat. Having the gas system in the stock required a small system or one made of slender parts, or the handguards got too bulky. You have to protect the shooter’s hand from heat, which means more bulk. Second, the height put the sights higher, which allowed for a longer point-blank range, important with a relatively slow cartridge like the M-43. Third, since the handguards didn’t have to enclose a gas system, they were made simpler, lighter, and thus had less effect on the barrel. Finally, the bore line was lower on the shooter, reducing muzzle climb due to recoil.
Each AK manufacturer made design changes that didn’t matter in the overall scheme of things but did make their lives easier. And now we have to deal with those design changes.
Simple fixtures like this allow you to squash rivet heads with ease, and several at a time.
These two receivers will require two different stocks.
However, it would be wrong to not point out that the cartridge part of it was beyond his control. Had the prevailing Soviet military requirement been to make a self-loading rifle in 7.62x54R, he would have done so (and actually later did). But as we discussed earlier, what the Soviet Army wanted was basically a submachine gun on steroids. What they got was much more than that.
As I mentioned, the first models of the AK-47 were designed and fabricated with sheet metal receivers. I have seen photos of transitional rifles that used a combination of sheet metal stamping and milled forgings, but they are not common. The Soviet intention was to make a rifle that was as inexpensive to produce as possible. Kalashnikov and Eugene Stoner agree about what their respective bureaucracies wanted: For Stoner, it was “light, light, light” and for Kalashnikov, it was “cheap, cheap, cheap.” If the industrial base of the country is set up to make more and more steel, it is relatively inexpensive to make products out of sheet steel. The other Soviet industrial base was cement, but you cannot make a rifle out of concrete. Alloying steel adds to the cost, so the AK had to be and is strong from design and not from alloys. That was a lesson the Germans learned in WWII. The FG42, a full-power rifle, was made from sheet metal stampings. However, to work with the 8mm Mauser, it had to be made out of expensive alloy steels and heat-treated exactingly. The AK is not made of high-tech tempered steel, nor heat or corrosion resistant alloys. It doesn’t have to be, using the 7.62x39. The sheet metal receiver is as strong as it needs to be for the job it does.
Most receivers use press-fit barrels, but some milled receivers use threaded ones.
Compare the forming ease of the AK receiver, below, with the G-3 receiver, above. You aren’t going to be making the latter on a multi-ton hand press, with a simple forming block.
The AK receiver with an earlier rifle receiver. The AK is a simple stamping, while the Mauser action requires hundreds of machining operations.
Some receiver designs use a threaded pistol grip plate riveted in place. Others use a “T” nut that sticks through a hole in the receiver (bottom).
You can see how simple the trigger guard is: a stamped loop, riveted to the receiver.
It must have drove Kalashnikov crazy, having to go from his simple stamped receiver to milled, in order to get rifles made.
More receiver stock variations, with each of these three, not only requiring a different stock shape but different attachment methods, too.
The Israelis had a better idea about sights (no doubt clued in by the Finns) and put an aperture sight on the rear of the cover.
The manufacturing of these parts was designed to be as inexpensive as possible. As a result, I would expect that a good set of stamping machines could produce receiver channels at a clip of better than one a minute. Even using antiquated Soviet production they had to be making them at the rate of more than 200 a day. That was one of the reasons making milled receivers was such a step back. You’d need many times the investment in machinery to make 200 milled receivers a day. From there, they’d go to heat treat. (Or, if the Soviets figured out just how to manage the alloys, heat treat first, then stamp. But I doubt that.) Once heat treated, they’d be pickled, parkerized and racked for assembly.
The barrel is a pretty simple thing: a steel tube with rifling on the inside and the outside turned to various dimensions. No profiling, no sculpting, just a cylinder of many steps. Especially, no tapers. The regular barrel-making machines could do that, as they had been doing for decades before.
Here’s where it gets interesting: The trunnions, rear sight pillar, gas block, and front sight housing are all castings. Once cast, they are machined only where needed. I suspect that once the bugs were worked out, and the rear trunnions designed and dimensions fine-tuned, the cooled castings ready for assembly never received a single pass from a milling machine. The gas block needs a lot of machining, though, and the front sight casting needs some, mostly the front sight installation areas.
The front trunnion takes a lot more work. Simply put, the idea of the Soviet production industry being able to cast a trunnion so the locking lug surfaces were “good to go” is absurd. So, the front trunnion received machining, mostly to locate and establish the locking lug surfaces.
The use of hydraulic rivet stations is obvious. Even a socialist organization, looking to create jobs for everyone, is not going to have hundreds of people wielding hammers or modified wire cutters to fasten rivet heads. So there would be fixtures and power. The machinists who did the work on barrel shanks, front trunnions, and barrel installation were probably the highest paid in the factory. (Hey, even in a socialist enterprise there are pay differences.) The relative diameters of the barrel shank and the hole in the front trunnion into which the barrel goes is critical. Too small a barrel and it wobbles inside the trunnion, and accuracy sucks — even for an AK — and reliability goes down.
Too large a barrel shank diameter and the hydraulic press that installs them works harder, wears, needs more maintenance and breaks down more often. Go even larger, and either the machine bogs down or the trunnions split. So the machinists who make barrels, and the machinists who make front trunnions, have to be in close communication with each other. Then, they have to pay attention to what the barrel installation crew tells them.
You can put a scope mount on it, but that doesn’t make the AK a sniper rifle. It barely makes it a decent dedicated marksman rifle, or DMR.
Just when you thought we were done with this nonsense, the Chinese come up with another stock attachment idea (left).
The Yugoslavians made their AKs with a reinforced front trunnion, then bent the sheet metal over it. If you have a Yugo parts kit, good luck with that.
A slight aside. Were I making AKs in a modern production facility, the first thing I’d insist on is threaded barrels. None of this communist wartime-expedient nonsense of pressed and pinned barrels, thank you. Trunnions would be machined with the front-face-to-locking-lugs dimension closely controlled. Barrels would be made with the stop-shoulder-to-headspace dimension equally closely controlled. Using modern machinery, it would be easy to produce barrels and trunnions that simply screwed together to a certain torque specification, and headspace would be correct.
Here the rivets attaching the rear trunnion to the receiver tube are clearly seen.
A standard front trunnion.
Rebuilding “neutered” imports creates scrap, like these now useless trigger guards, yanked off of Saiga rifles.
Shown next to an installed one, you can see what the front trunnion does when riveted in.
The barrels would be stainless. They could have the gas port drilled, and the various parts installed while held in fixtures. No tilted front sights.
But, that wasn’t an option for the Soviets. So, the process went something like this: barrels would be pressed into trunnions, with the assembler checking headspace. Once the headspace was within acceptable limits, the set were racked for the next step, and the cross pin hole would be drilled.
Those of you who worry about headspace when home-building an AK should save your money. If the headspace is off, there is nothing you can do about it. That barrel and trunnion were “married” at the factory with that bolt. The only thing you can possibly do to change headspace is to swap bolts. Barring that, you have absolutely no options for adjusting headspace on your build. None. The headspace was set by Yuri and the gang back in Mother Russia or Bulgaria, Romania, wherever, and there is no provision for changing it after the fact.
Also, the bore and chamber are hard-chromed, except on Yugoslavian AKs. If the chrome is at all present, you’ll be doing a lot of harm to your chambering reamer trying to adjust insufficient headspace on an AK barrel. Too much headspace? If you reload or plan to reload, that could be a problem. Then again, if you treat your AK like a real rifle, and not just a “surplus ammo eatin’ machine” you can adjust your reloading dies to compensate for excess headspace.
Which brings me to another point: We have had a lot of fun with our AKs in the last couple of decades. We’ve been treated to a flood, a torrent of ammunition at prices so low that you had to wonder how the makers made any money at it. Basically, they didn’t have to. The imported rifles kept people back home working until the economy could be retooled to provide real jobs and real manufacturing. The ammo? That was just laying around in warehouses, left over from the old communist days, and could be better used getting sold for hard cash. Ditto the parts kits. No one wants to buy new AKs, not when the market in the world is awash with old ones, clogging arms bazaars, filling the storage rooms of international merchants of death. No, we Americans are the only ones who will pay money for new, and we’ll even pay money for old stuff if it is properly busted up into scrap.
To get the carrier in and out, Kalashnikov simply cut slots in the top rails, where you lift the carrier out once the top cover is off.
Front sight and gas blocks come in a large variety. The purists hate “mis ‘n match” guns, but if it works, who cares?
You have to attach a lot of things to a barrel to make it useful. Here is the front end of an AK-74, gas block, front sight, and muzzle brake.
The rear sight pillar nestles in the front trunnion shoulders.
The bolt and carrier ride over and on the rails created by folding over the top lip of the receiver, and spot-welding rails underneath.
This rear trunnion is made for a folding stock, a sidefolder to be precise.
You have to wonder at the workmen in the plants; cutting and torching the very rifles that they had so carefully assembled to fight the good fight against the capitalist market-force hordes who were now buying the AKs they now had to scrap. Oh, the irony.
One thing is for sure: the very aspects of the Soviet command-economy that made the AK inexpensive to produce make it amenable to hand-manufacture here in the States. All you home-builders, be glad the Soviets were mechanized only in their Infantry. 