Subsonic 7.62x39 loads that cycle an AR.

[rossi]

Has anyone on this forum been able to safely load any?

rossi

 

[Recondo 101]

I designed and built the first fully functional AR-15 posted on the Grendel forum for a 6.5 Grendel. The loads would be similar as the 6.5 Grendel is based on the 7.62x39 case, in a line of case modifications. I just die form 7.62 cases to 6.5 Grendel then fire form.

So the sub loads with the case capacity are 9-10 grains of H-110/296 which is the same powder, with a 200+ grain bullet. Your speed of sound should be similar to mine at about 1,100 fps, so you want to stay at or near 1,000 due to the standard deviation which can be wide with low loads.
I reduced the recoil spring by two coils, buffer weight, polished the BCGs bearing surfaces and used .267 bullets VS .264 bullets to increase the pressure while the bullets were in the 16" barrel only for increased function. This was all done in order to achieve full function from the magazine with a can.
With the 6.5 Grendel and 160 grain RN soft point bullets, the bullets still penetrated 11 stacked, dry, P cola phone books and 6" into road bed clay.
To increase energy at subsonic velocity you must increase bullet weight, not velocity, once you reach the speed of sound.

 

[rossi]

I'm looking for a "Proven 7.62x39 Sub-Sonic". I'm not going to flirt with danger. If necessary, I'll buy the ATOMIC's at $90.00 per 50 rounds.

 

[Rebel_Rider1969]

I'm looking for a "Proven 7.62x39 Sub-Sonic". I'm not going to flirt with danger. If necessary, I'll buy the ATOMIC's at $90.00 per 50 rounds.

Brown bear makes em too. 3 brothers in baldwin County had em.