Regarding the guys original post, it seems that the concern is recoil. He asks for a cartridge with more energy than a 7.62x39 with less or no more recoil. We are not addressing the issue, and we must remember basic physics in response. The bullet energy is identical to the recoil energy minus the weight of the gun. Keeping a constant weight gun, any increase in bullet energy will give a proportionate increase in recoil, caliber being immaterial. It doesn't matter how that bullet energy is increased, be it speed or bullet weight. Bullet diameter is not a factor. Energy is mass (bullet weight) times speed. Within practical terms, energy of any given bullet is restricted by speed--we can't increase speed indefinately. That is why we have bigger calibers to get more energy. Higher energy gives a larger degree of error allowance in regards to killing animals. If one chooses to hunt deer with a .458 Lott, he has a larger degree of error allowance than if he uses a .338 Win Mag, which allows for a bit more error than a .30-06, which allows more error than a .243 and so forth down to a .22 short (which can and has killed deer). Now someone will jump up and down and say that bigger guns DON'T replace skill. Very correct, but the fact is that bigger DOES provide more room for error. Shoot a deer with a .600 Nitro Express and it is going down as long as you hit the body somewhere (and maybeso you are too!). The whole point is that the energy cannot be increased without increasing recoil and bullet diameter is not a factor. Of course the recoil can be counteracted by having a heavier gun. The original poster didn't want a .30-06 because of recoil, and that's fine, but simply for illustration, if that .30-06 were to be a 25# gun, the recoil would be minuscule--not practical, but factual. So, if he wants more energy than a 7.62x39 with no more recoil, he can get it in any number of ways, but the rifle weight must go up enough to compensate for the increase in energy to maintain equal recoil. It is simple physics and can't be altered.