Cortina Precision. muzzle device

[Bassfish1952]

1/2-28 tpi threads... so this is for a 556?
Most 6 Arc and grendel barrels have 5/8-24 threads.
There's a minimum barrel thickness for proper threading, so the walls are not too thin by the threads.

No I have a 6.5 CM with 1/2-28 and checked before ordering this for my 6arc  
we’ll see how it works