Gemtech Tri-Lock .338 Lapua Muzzle Brake for Arrow QM Suppressor 5/8-24 Black. 338 ARROW Muzzle Brake is for users who want less felt recoil less muzzle climb and faster follow up shots. The .338 Tri-Lug Quick Mount is for the GEMTECH ARROW Silencer and comes in multiple thread pitches. Specifications for Gemtech Tri-Lock .338 Lapua Muzzle Brake for Arrow QM Suppressor: Manufacturer: Gemtech Color: Black Caliber: .338 Lapua Magnum Additional Features: Quick mount for Gemtech Arrow Package Contents: Gemtech Tri-Lock .338 Lapua Muzzle Brake for Arrow QM Suppressor Gemtech 12143: Tri-Lock .338 Lapua Muzzle Brake for Arrow QM Suppressor 5/8-24 Black