For 10.4 inch barrels.
This SBR muzzle treatment fits all P90 length barrels but hand fitting may be required.
The exterior threads are 1/2x28, the standard threads for muzzle brakes, flash hiders, and silencers.
Remember, the internal threads are left handed so you will be screwing in the barrel lefty-tighty. Visually inspect your silencer for concentricity after initial mounting. There is a potential for baffle strike since 3 sets of threads have to be manufactured perfectly concentric. If you encounter an issue we can fix it.
Side Note: The PS90/P90 is a poor silencer host. The direct blowback action is already at the limit for sealing the breach. When you add the back pressure from a can you get a blast of gas that will foul the breach area and can dislodge your mag, plus excessive bolt velocity which causes problems as well.
