Abstract: A mount for mounting a firearm sound suppressor or silencer to a firearm muzzle or muzzle device operates by using primary mounting lugs on the suppressor which engage sockets on the muzzle device. The primary lugs prevent the suppressor from axially moving with respect to the muzzle device, thus causing them to be fixed together as a unitary device. Angled bearing faces on the muzzle device and the sound suppressor are pressed against each other by rotating the sound suppressor on threads which drive the angled bearing faces together, thus tightening the primary lugs within their sockets. Backup lugs on the silencer engage an annular groove on the muzzle device to retain the silencer on the firearm to which it is mounted in case of failure of the primary lugs. Rapid attachment and detachment are supported by these structures.