Today at the range, I'm shooting my CZ 527 - 7.62x39.
I have with me a couple of different rounds and will see how they group at 100 yards.

 

 

I'm shooting:
Barnual / MFS 7.62x39 - 123 grain FMJ's
Barnual / MFS 7.62x39 - 125 grain Soft points.
Hornady 7.62x39 - 123 grain SST
Winchester Super-X Ammo 7.62x39mm - 123 grain Power-Point
Federal American Eagle Ammo 7.62x39mm - 124 grain FMJ

The Barnual / MFS seem to shoot very well, I suspect the bullet diameters are .311, the Hornady and Winchester not quite as well, because I suspect they're .308 diameter bullets, the Federal American Eagle shot very well out of my rifle, even with my lousy shooting.

I love my little CZ 527 Carbine, I'm seriously considering scoping the rifle to see what it can do.