Thespeed of the 7.62x39 and the 30-30 are both around 2000 ft/sec. How do I know this? I load both rounds and have put them through a chrono.(1980 ft/sec). The .308 is around 1000 ft/sec faster. This gives it much better hitting power. The .308 is far superior in accuracy and why it is the sniper's choice.