Handloads for the 7.62x39
Date: Jan 13 2009
If you were to examine in detail what each cartridge can offer the shooter or hunter, you might find some things you’ve overlooked. The 7.62x39, made famous by Mikhail Kalashnikov, who designed the AK-47, is a good example. Rarely considered to have a sundry of uses, this Russian military cartridge will surprise you with its diversity, especially in a bolt rifle where it’s not required to operate the action. Even though most Americans were first introduced to it from the bullet end during the Vietnam War, it has become at least moderately popular here in the States.
My interest in the 7.62 has been only marginal since I attended an OPFOR (opposing force) weapons class in the service. However, when CZ offered its Model 527 carbine in this chambering, I considered experimenting with it. I’d all but forgotten that when a friend called not too long ago and told me he had purchased one of the cute little rifles. “I want to use it on everything from fox squirrels to whitetails. Want to help with the load work?” Like a lawyer, he already knew the answer to that question or he would not have asked it.
Our goal was to produce three loads with different uses in mind for each. We wanted a deer-hunting load, something that would offer ballistics similar to the 150-grain .30-30 Winchester. We hoped to find an accurate varmint load suitable for ground hogs, coyotes and fox. And, we wanted to develop a super-accurate, low-velocity, cast bullet load that could be used for squirrels and turkeys. We also wanted this low-recoil round to be inexpensive to produce, providing ammunition for practice and training new shooters.
Multiply 7.62 millimeters by the conversion factor listed in the Speer Rifle & Pistol Reloading Manual 13 and you get .2999994 inch, which for all practical purposes is .30 inch. If you pull the bullet from a 7.62x39 cartridge and measure the diameter, it will be somewhere between .308 and .311 inch. It varies from manufacturer to manufacturer. Some 7.62x39 bores like those from Ruger will measure .308 inch groove to groove. Factory ammunition with bullets from .308 to .311 inch will work in either a .308- or .311-inch barrel, just don’t expect sub-MOA groups. At least that’s what I thought. (Most reloading die manufacturers offer both .308- and .311-inch expanders with 7.62x39 dies.)
The deer load came easy. We found a slightly compressed charge of 25.5 grains of Reloder 7 produced 2,222 fps out of the short 18.5-inch barrel with the 155-grain Sierra bullet. Groups at 100 yards averaged .88 inch. We tested this load in wet paper at 100 yards where the impact velocity was 2,029 fps, and the bullet showed good expansion and weight retention. The Speer 150-grain load was just a trifle slower, and groups averaged 1.3 inches but did not hold up as well in the wet paper.
With the deer load in the box we started on a lighter bullet load for varmints. The 125-grain Sierra bullet was the winner again at 2,245 fps with 100-yard groups averaging .97 inch. Zeroed 2 inches high at 100 yards, it will strike about 3.5 inches low at 200 yards. Starting out at 2,166 fps, the Hornady 123- grain bullet came in second, producing consistent, near one-inch groups. Velocities were not substantially higher with these lighter bullets, but recoil was noticeably less.
Even though the rifle had a .311- inch bore, I wanted to handload some .308-inch bullets. The plan was to work up to 25.5 grains of Reloder 7, a powder this cartridge really seemed to like, using the long Nosler 150-grain Ballistic Tip. With a maximum overall length of 2.302 inches – dictated by the detachable magazine – I ran out of case capacity with a compressed charge of 24.5 grains. I loaded up nine cartridges and fired three, three-shot, 100-yard groups that averaged .80 inch.
The Nosler 150-grain Ballistic Tip also performed well in the test media at 100-yard impact velocities. So much for a bullet to groove difference of .003 inch being severely detrimental to accuracy. To resize a fired 7.62x39 case that used a .311- inch bullet so you can load a .308 bullet, simply switch to the .308 expander and full-length resize in a Redding die.
It took some work to get an accurate, low-velocity, cast bullet load, but finally we loaded the 155-grain NBC hard cast bullet ahead of 18 grains of IMR-4895 and locked them in with a generous crimp. With a muzzle velocity of 1,120 fps, the average for the three, five-shot groups at 60 yards was .480 inch. With this performance we saw no reason to look farther for a small game/practice load.
Be aware that some 7.62x39 brass utilizes a small rifle primer and some a large rifle primer. Federal brass provided best accuracy and slightly higher velocities. Whether this was due to the large rifle primers, the brass itself or the combination, one can only speculate.
If you are building or buying a 7.62x39 and are arguing with yourself over bore diameter, consider that most .308-caliber spitzer bullets are not designed to provide their best terminal performance at 7.62x39 impact velocities. And, even though there’s not a wide selection of .310 and .311 bullets, those available are just the right weight and length for the 7.62x39 and do provide good terminal performance.
Regardless of its country of origin, the size primer used or the bore diameter, we managed to meet our goal of producing a handload for deer, varmints, small game and practice. Hmm. Seems like a fairly diverse cartridge to me. If nothing else that makes it politically correct by the corporate standards of the new millennium.