Muzzle Brake for a 308

you can see many are very similar (from Lug Nut's link).
i am also running a surefire, although it is a version that accepts a surefire suppressor. (same as the M40A6)

308-brakes-chart2.jpg
 
I have run the Surefire and Precision Armament. Both worked. I like my Surefire but it is on a 7.62x39 bolt gun which does not really need it. But it feels like a .22. The Precision Armament was on a 338 Win Mag and worked well.