I have the 30 cal DeadAir Sandman-S. A downside, if you can call it (see any porting/braking thread), is the requirement for a key mount muzzle brake at ~$80 per unit. But, it's extremely versatile. I run it on all my MSRs, my 6.5, 308, 300 Win Mag, etc. And if I ever hit the Powerball, it's...