Compromising the two 7.62x39mms
What Bushpilot said about the difference in diameter within the same caliber is a the reason I shy away from the Mini-30, ARs in 7.62X39 or any other non-Russian design.
I'm not a Russian gun fanatic, but I've owned several AKs and SKSs.
U.S. manufacturers face a dilemma the Soviets didn't have to worry about: Winchester makes a round in that caliber that's 2mils wider than the Russian round. If Ruger made the barrel to accommodate that bullet, Russian rounds that were fired from it would shoot horribly, and the pressure leakage would do serious damage to the barrel.
This is what backs me off from getting an AR upper in that caliber. I remember some guys in a gun store backordering Rossi Wizard barrels in that caliber. I asked them if they'd read the Spec. Warning that cautions against any use of Russian .30 ammo.They shrugged it off with a "It's close enough!"
Ruger came up with the only feasible compromise that would fire both rounds safely and without rapid barrel damage. They made the barrel just small enough for the Russian diameter, and they put in an extreme forcing cone to resize any potential Win. .30s down almost 2mils to come up with a gun whose accuracy can, at best, achieve the lower level of 'acceptable'. If you're making close, sure-thing shots, you'll be satisfied.
If you compete for popping golf balls at 50 yds., it'probably won't win you over.
I don't know why so many shooters want to accurize that caliber, in the first place. It's a bit overweight for the speed it's supposed to reach.
- 2300 FPS from a 124gr. bullet?