The action type switch is located at the forward end of the forearm, and is formed as a winged and spring loaded nut just behind the annular knurled ring.

This improves the versatility of the shotgun, allowing it to fire low-powered ammunition (mostly of special purpose, such as less-lethal rubber or tear-gas projectiles) in the manually operated pump action mode, and to fire full power combat loads with slugs or buckshot in semi-automatic mode.

An underbarrel tubular magazine usually holds 8 rounds for police or military versions, or less in some civilian models.

This is an interesting feature for weapon modification, since other shotguns (such as M1, M2 and M4) attach the butt-stock to the recoil spring tube.

A rare modification is to replace the M3 butt-stock and dummy rod with a "Benelli SuperNova Handle Grip".