An apparatus and method for locking a gun. The apparatus includes a dummy round
configured for insertion into a firing chamber of a gun, a locking component configured
for coupling with the dummy round, and an elongated sleeve rotatably coupled with
the locking component. The locking component includes a keyed head positioned within
a longitudinal channel of the elongated sleeve. The locking component and elongated
sleeve are insertable through the discharge end of a gun's barrel. An actuating
mechanism, such as a key is insertable through the channel of the elongated sleeve
to engage with the keyed head and rotate the locking mechanism relative to the
elongated sleeve. Rotation of the locking mechanism effects a friction lock between
the locking mechanism and the dummy round.