A system for connecting an accessory to a firearm having an enlarged
muzzle portion has a body with a bore sized to closely receive the
enlarged portion. The body has a stop to limit the insertion depth of the
muzzle. A gate is received by the body for movement along the path
perpendicular to the bore axis. The gate has a recessed area sized to
receive the enlarged muzzle portion. A spring generates axial force to
retain the muzzle portion within the recessed area. Compression of the
spring enables movement of the gate to shift between an open and closed
position, so that the accessory may be removed or installed when in the
open position, and secured when in the closed position.