[Blackhawk]

World of difference between 100yds and 600yds. The 7.62x39 max powder load MV isn't enough to get a 125gr. bullet out to 600yds with any degree of accuracy. At 100yds fine, a lot of lead on target with a medium amount of ft/lbs of energy. To get that same bullet down range to 600yds and hit what you want to you really need to go up to the 7.62x51 NATO (.308) which will hold almost twice the powder load and an extra 1000 fps MV which will keep the bullet in the air with enough energy to keep it true to target. That is where the 5.56 NATO has the advantage. For the size and weight of the bullet (62gr. for the SS109) it has a huge powder load and MV which keeps it almost flat out to 400yds. That makes BD calcs pretty easy at 600yds.

[PugetSoundSoldier]

The Kel Tec RFB is 7.62x51mm. It’ll get to 600m with enough energy to still get the job done!

[Still Thinking]

World of difference between 100yds and 600yds. The 7.62x39 max powder load MV isn't enough to get a 125gr. bullet out to 600yds with any degree of accuracy. At 100yds fine, a lot of lead on target with a medium amount of ft/lbs of energy.

7.62 Commie is roughly equivalent to a 30-30. Anything you wouldn't try to do with a 30-30 you shouldn't try to do with an AK. And yes, 308 is a big step in the right direction.