Reloading the 7.62x39
February 03, 2011
The AK47 and its numerous variants are certainly on the very short list of guns that have been produced in the highest volume. The gun has proved to be great for what it was designed to be — an assault rifle. The ammo it uses is the 7.62x39 Russian, a modestly sized little bottlenecked number that fulfills its military tasks very well. The case also provides a wonderful option for introducing young or recoil-sensitive shooters to centerfire rifle shooting.
In the AK47 and SKS variants (none of which is actually an assault rifle, because they lack a full-automatic capability) sold in this country, the accuracy of the 7.62x39 is rarely anything to write home about. But in assault rifle mode, accuracy isn't the primary consideration. Accuracy depends largely on pushing good bullets through a good barrel. Almost any cartridge shape can be made to shoot well if those two conditions are met. The 7.62x39 is no exception.
Let's talk about bullet diameter for a moment. Since the AK47 variants have been made all over the world, bore diameters are all over the map as well. Some are as small as .308, and some are well over .312 inch. Since the more or less nominal groove diameter for 7.62x39 is .310 inch, and the SAAMI standard for bullet diameter is .310 minus .002, regular .308 bullets meet the spec. But you shouldn't be a bit surprised to find guns chambered in the U.S. for this cartridge that use a .308 groove diameter.
All the bullets used in the loads listed here are standard .308 diameter. They are safe to shoot in the AK47 variants, and all shot very well in our .308-groove-diameter pressure barrel. The .310 bullets that are available for the 7.62x39 may very well produce somewhat higher pressures than you would want if fired in a .308 barrel, so you need to know the barrel dimensions of your gun. If you substitute .310 bullets for the bullets in the table, you must drop back to the starting load level and proceed with caution.
The supply of cases for reloading is not a serious problem, but it does require some care. There's plenty of foreign-made ammo in this caliber, and I would suggest avoiding it for several reasons. The first is that the quality varies wildly. Second, much of this stuff has steel cases that are a pain to reload. Third, much of the foreign ammo uses Berdan primers, and that severely complicates reloading. I used Winchester cases and IMI. Yes, the IMI are foreign-made, but I know from sectioning some that they are brass and use standard American Large Rifle Primers. Federal, Cor-Bon, Remington and Sellier & Bellot all build ammo in this caliber, so case supply isn't a problem. The primer supply, which has been terrible for so long, is opening up a little. All the loads listed use Standard Large Rifle primers, although Magnum Large Rifle primers could be used if necesary. This is a substitution that underscores a fact-of-life premise: Whenever you change anything, always drop back to the starting load level and work up carefully from there. Generally, Magnum primers won't significantly increase chamber pressures if the Standard primers were giving good ignition in the first place. But why take a chance? Drop back and work up again.
Dies are readily available. I have a set from Lee Precision that came with two neck-sizing plugs, one for .308 and one for .310. I used the .308 size because it fit the bullets better. Finally, powder selection is very good. The powders most suitable can be found — as you might expect — either at the fast end of the rifle list or, with very light bullets, at the slow end of the pistol powders.
A word about bullet weights. The typical military load for the 7.62x39 uses 123-grain bullets. Our pressure barrel, which was 1:10, shot these and bullets up to about 150 grains very well. We did shoot some 160-grain bullets (see chart) and noticed some evidence of yawing on the target. If I were building up a gun for the 7.62x39 and wanted to shoot heavy bullets, I would use a 1:8 barrel. If cartridge overall length is a consideration, the heavy bullets intrude too deeply into the case and use up case volume. That compromises performance. Of course, in single-shot guns you can modify the throating to allow a longer cartridge OAL.
The 7.62x39 cartridge is just about the perfect size for new shooters. With the current crop of premium bullets, the cartridge becomes plenty adequate for deer hunting applications. There are even lead-free bullets for places where you are required to use them. The FMJ bullets found in much of the cheap foreign-made ammo in this caliber should be avoided like the plague.
This is an interesting little cartridge that is specially applicable to single-shot, long-barrel pistols. And unlike some of the big boomers, the 7.62x39 is a lot of fun to shoot.