does the 7.62x39 have better ballistics than the 30-30? I've shot pretty hot loads in my marlin lever that have a lot more kick than the lighter AK.
Within 100 yards, the .30-30 is usually going to hit harder. .30-30 usually uses 150 grain or 170 grain bullets whereas the 7.62x39 is usually using 120-125 grain bullets.
I'd say on average the .30-30 is launching the 150 grain bullet around the same speed the 7.62x39 is launching a 125 grain bullet.
If you are using round nose bullets in a .30-30 the ballistic coefficient advantage of the 7.62x39 will have it hitting harder past 120 yards or so.