SwissyJim,
What weight are you thinking of shooting? I have a 300Blk, and the 1:8 is optimized for the 205gr sub sonic round. Hornady makes a stellar projectile for it. It also shoots the piss out of the 110, 115 and 125 grain stuff I've been shooting.
I know there are 220gr and 240gr out there that would excel in a tighter barrel, but I'm pretty sure those are just FMJ/Ball ammo. Good for pokin holes... and that's about it.