You're building a 300 BLK to shoot 220g subsonics through your .30 can, when it gets out of ATF jail, right?
(I'm just assuming, why would anyone else want a 300 BLK?)
I mean, a 300 BLK without a can is like peanut butter without the jelly, but I digress.
I have a 8.3" Ballistic Advantage...