FWIW, I recently obtained a rare Savage Scout rifle chambered in 7.62x39, and it reportedly has the "American" .308 bore. I was fine with this since I eventually planned to handload for it anyway, and figured the .308 would give me more choices, as well as give me a common platform for my .308 Win, 30-30, and the 7.62.
What I discovered after trying 4 types of factory loads is that the bullet diameter really doesn't matter in my gun. I fired two brands of Russian surplus FMJ's that were .308 and .309" bullets by my measurements, and they gave me respectable 2" groups at 100 yards all day. I also fired .309" Winchester Hog Special and .310" Hornady SST (steel case) through it, and both gave me MOA groups out to 200 yards. I routinely shot 1.5" at 150 yards and 2" groups at 200. What's more, both the Winchester and the Hornady shot to the same point of impact out to 200 yards, despite having different bullet diameters.
So I would say try it before you decide. I am more than happy enough with the accuracy of the Hornady ammo that I have decided not to buy any reloading equipment at this time for the 7.62x39 scout. I could probably wring out a little more accuracy with a lot more effort with handloads, but I don't think it would be worth it, as my accuracy with the factory hunting loads is more than acceptable at the ranges I intend to use this caliber rifle.
