A carrier assembly for a gun comprises a gun bolt carrier disposed to reciprocate
axially with respect to the central axis of the gun, and a gun bolt disposed to
reciprocate axially within the carrier. The gun bolt has a locking groove therein.
The assembly also comprises a bolt locking mechanism extending through a portion
of the bolt carrier to selectively engage the locking groove and thereby prevent
the bolt from moving with respect to the carrier. The assembly further comprises
a generally axial groove in a non-reciprocating portion of the gun that engages
and selectively rotates the rotatable bolt locking mechanism to selectively lock
the bolt to the carrier.
