I have some 150 grain .310 projectiles (pulled from military surplus 7.62x54R I think) that I am trying to develop a load for in 7.62x39.

The projectile is quite long for the cartridge, but it sure seems like it ought to work. 

I can get eight inch groups at 100 yards, but I'd like to cut that in half.

Has anyone attempted to build a similar load?