hand loading 7.62x39

[clueless]

I found Belom 7.62x39 to shoot quite well in a 16" AR with 7.62x39 barrel. The barrel is from Hitman Industries, has carbine gas and 1:10 twist. The Belom rounds have a reloadable brass case. Having some 225gr Gallant powder coated bullets in .310" diameter, there was an opportunity to try hand loading some 7.62x39 rounds. I was not able to find any load data in this caliber for bullets this heavy, so looked at 300 BLK loads as a baseline and worked up. Please note - I am no expert at hand loading and cannot recommend that anyone try what I did. It made sense to me but I don't know that it is safe. I welcome all comments.

I settled on a starting load of 10.4gr Accurate 1680, with CCI #34 primer. It was necessary to expand ( Lyman M-expander ) the case necks to avoid shaving off the coating. I seated the bullets at 2.23", which is longer than the 2.20" allowed for 7.62x39, but still gave about .030" to the lands in my barrel. I loaded two rounds, and two rounds each in successive increments up to 13.9gr. There were occasional FTF on the first round where the first round did not get stripped from the magazine ( Duramag steel 7.62x39 ). However, for the load at 11.9gr and all above that, the rifle cycled and locked the magazine open after the second of two rounds.

Chrono results:
10.4gr - 905fps
10.9gr - 927
11.4gr - 1003
11.9gr - 1067
12.4gr - 1100
12.9gr - 1122
13.4gr - 1162
13.9gr - 1226

I can't say much about accuracy other than that I did not see any obvious cause for concern. I shot at targets 50 yards away and all the holes were perfectly round. Each load hit a little higher on the paper than the previous. There was no sign of distress in the primers. If I try this again I would adhere to the 2.200" COAL in the hope that the first round feeding would improve. There is probably also the potential for higher velocity if one is not concerned with staying subsonic. For subsonic, the 12.4gr load seems workable. Maybe fine tune that number at the shorter COAL and see if the bullet is still flying true at 100+ yards.

Regarding the Gallant bullets, I bought them at Sportsmans intending to load 300 BLK. Something like $75 for 500. The box says .30 cal 217gr boat tail TPJ - Total Polymer Jacket. I could not assemble any round with them that would chamber in 300 BLK without going down to an extremely short COAL. This all became clear when I measured them at 225gr and .310" diameter, which is one of their stock items.

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[fstdraw]

Hmm, why go thru all that trouble? I understand experimenting, but that's a heavy bullet! There might be a slug of .308 bullets that might have more range, and still be heavy. Good luck and let us 7.62x39 loaders how it goes.

 

[clueless]

I think that the main interest is in making a subsonic round in 7.62x39. These initial results suggest that it is practical, and I thought others might be interested. A few companies are selling loaded subsonic ammo in this caliber. Item X39225TPJ from Detroit Ammo Co looks like it uses the same bullet too. They are asking about $1.10 per round - the others are $1.20 and above. What I am describing would be one fourth of that, should someone be interested.

There is not as much motivation for pushing a 225gr supersonic. Assuming that one could get to 1300 fps safely, I took a guess at G1 ( 0.35 ) and plotted trajectory to 100 yards. With zero at 85 yards, one would hit within 1.5" of the POA at any distance out to 100 yards. At 100 yards it is still moving at 1176 fps with 686 ft-lb energy, and an impressively high SD. Certainly good for plinking if nothing else.

308 bullets would open up a lot of possibilities but my understanding is that some 7.62x39 barrels are .308" and others .310". Is it the case that one can shoot .308 bullets in a .310 bore and still get acceptable performance ?

 

[VinnieBoomBah]

308 bullets would open up a lot of possibilities but my understanding is that some 7.62x39 barrels are .308" and others .310". Is it the case that one can shoot .308 bullets in a .310 bore and still get acceptable performance ?

Only one real way to find out, but over the years I have seen enough test to believe it can be a worthwhile experiment
Keep in mind I have seen loads that will shoot lights out in one gun not be able to hit the side of a barn from inside the barn when fired from another gun

 

[JSAV97]

It sounds like you have a decent subsonic load there, which would suppress well. I would recommend a 180 grain bullet if you want something heavy for caliber, but also want accuracy past 100 yards.

 

[clueless]

... I would recommend a 180 grain bullet if you want something heavy for caliber, but also want accuracy past 100 yards.

Make sense for a supersonic load. If staying subsonic then the heaviest bullets could have better BC and more energy at any range, no ?

I haven't done much with 7.62x39 for a while, but did try loading some .308 diameter bullets to see if they would shoot in my rifle with a .310" bore. The 125gr SST with 26.3gr Accurate 1680 produced a roughly 3.3 MOA group. Likely a little better with a better sight, but I was able to manage 1.5 MOA with a 123gr PPU PSP having .310 diameter. This was the only load that I tried.

 

[JSAV97]

Make sense for a supersonic load. If staying subsonic then the heaviest bullets could have better BC and more energy at any range, no ?

I haven't done much with 7.62x39 for a while, but did try loading some .308 diameter bullets to see if they would shoot in my rifle with a .310" bore. The 125gr SST with 26.3gr Accurate 1680 produced a roughly 3.3 MOA group. Likely a little better with a better sight, but I was able to manage 1.5 MOA with a 123gr PPU PSP having .310 diameter. This was the only load that I tried.

I've found that if you have a .310 bore, you won't really see any difference between .308 and .311 bullets (unless you're shooting past 500 yards maybe). I have a Mosin (7.62x54r) with a .310 bore and shot a 1 MOA group at 200 yards with a 180 grain Hornady SST. I've used .308 bullets out of my 7.62x39 AR as well. Still capable of 1 MOA groups. With a good optic and rest, you could get sub MOA with your 125gr SST's. Also I might try out your load data, I've been wanting to set up my AR as a brush gun for hunting black tail and coyotes.

 

[clueless]

Also I might try out your load data, I've been wanting to set up my AR as a brush gun for hunting black tail and coyotes.

In my AR, I settled on a Spike's T3 buffer with standard spring. I loaded the 225gr Gallant at 2.200" COAL. Everything with 225gr bullets from 11.9gr and up in 1680 would lock the bolt back on an empty magazine. My latest experiments only consisted of 5 rounds of the 225gr @ 12.9gr 1680, 10 rounds of 123gr PPU @ 26gr, and 5 rounds of 125gr SST @ 26.3gr. There were no issues feeding or cycling any of the loads.

Please share your findings if you try this out.

 

[El Mariachi]

I think that the main interest is in making a subsonic round in 7.62x39. These initial results suggest that it is practical, and I thought others might be interested. A few companies are selling loaded subsonic ammo in this caliber. Item X39225TPJ from Detroit Ammo Co looks like it uses the same bullet too. They are asking about $1.10 per round - the others are $1.20 and above. What I am describing would be one fourth of that, should someone be interested.

There is not as much motivation for pushing a 225gr supersonic. Assuming that one could get to 1300 fps safely, I took a guess at G1 ( 0.35 ) and plotted trajectory to 100 yards. With zero at 85 yards, one would hit within 1.5" of the POA at any distance out to 100 yards. At 100 yards it is still moving at 1176 fps with 686 ft-lb energy, and an impressively high SD. Certainly good for plinking if nothing else.

308 bullets would open up a lot of possibilities but my understanding is that some 7.62x39 barrels are .308" and others .310". Is it the case that one can shoot .308 bullets in a .310 bore and still get acceptable performance ?

I load 150 and 165 BT, for Howa 1500.
Barrel is .310, with the ample bearing surface of the heavier bullet it seams to stabilize fairly decent.
Grouping is acceptable for me, which is under 2moa.
24 grains of Alliant 2200 for 150, 22 grains for 165.
No pressure issue signs.