Gemtech 22-QDA 1/2-28 Rimfire Suppressor Adapter - The Gemtech 22-QDA is a universal adapter for all rimfire silencers that allow attachment and detachment quickly and efficiently. The four-lug muzzle device is threaded 1/2-28 to mount on all standard rimfire threaded barrels for maximum compatibility. The 22-QDA mount is threaded 1/2-28 for use in all 22LR and 22MAG rimfire silencers. 1/2-28 Thread