Surface treatment: Nitriding
Taper at the front of the thread ensures solid lock up and minimal/repeatable POI shift and it also effectively blocks fouling from entering the mounting surfaces.
The heat resistant o-ring behind the thread secures the suppressor tightly on the flash hider and suppressor will not loosen up by itself. The heat resistant o-ring peak temperature resistance is 400c degrees. In our test the muzzle device temperature, with AR15 equipped with 5.56 Compact Streamer, was 280c degrees after 6 x 30 rounds magazines in row.
A2 flash hiders are for 5.56 and 7.62 calibers. The bullet channel is 8,5mm.