Hypothetical 7.62x39 question

[BoringGuy45]

My understanding about the x39 is that due to it's low BC, it has a quick drop out past 200 or so yards. If the bullet was changed from a .310 to a .308 (same weight and length obviously), would it a) have a noticeably higher BC and b) be compatible with most 7.62x39 barrels (AK, AR, etc)?

[TiroFijo]

No difference in BC.

Most 7.62x39 rifles have .310" bores, but can shoot .308" bullets just fine, accuracy wise.

[481]

My understanding about the x39 is that due to it's low BC, it has a quick drop out past 200 or so yards. If the bullet was changed from a .310 to a .308 (same weight and length obviously), would it a) have a noticeably higher BC and b) be compatible with most 7.62x39 barrels (AK, AR, etc)?

Domestic 7.62x39 ammo loaded by Winchester, Remington and Federal all use .308" diameter projectiles with respective BCs of 0.250, 0.266 and 0.295. They all run quite well in 0.310" bores, at least in my experience.

The 7.62x39's long range performance (200 yards and out) is effected not only by these relatively low BCs, but also by the fact that being an intermediate cartridge, it operates at a somewhat lower muzzle velocity.

These factors combine to make the 7.62x39 a 300-400 yard proposition at best.