Abstract: The invention relates to a hand-held firearm comprising a muzzle silencer (9) and a barrel (11) which is provided with transverse bores and is surrounded by an expansion area (15) into which the transverse bores extend. The transverse bores (14) enable the muzzle velocity of the bullets to be less than Mach 1, in spite of the use of conventional ammunition, and there is consequently no supersonic boom of the bullet. To selectively eliminate the reduction in firing energy involved therein and be able to shoot with maximum firing force, the transverse bores (14) are selectively closable by a locking device (16) which is preferably in the form of a sleeve (16) which surrounds the barrel (11) and is mounted for rotation thereon and is furthermore provided with an actuating member (21) for setting the open or closed position.