The silenced .22 SMG is a distinctive weapon with its unusual pan magazine, which sits atop the gun rather than under. The silencer is integrated into the barrel with no modifications required.
However, it shares the common weakness of most shotguns and automatic weapons in Fallout: New Vegas, in that much of its theoretical power is negated by the Damage Threshold system. In addition to losing much of its damage, the high spread of this weapon requires the player character to be at close ranges for all of the rounds fired to impact on the target.
With the expanded drums mod, the iron sights also appear to be modified slightly, as they would need to be raised to accommodate the larger pan magazine.
The Silenced .22LR SMG is one of few weapons that has its own unique reload animation. No other gun has this reload animation and it has no unique counterpart, making it one of only two weapons to do so (even with all add-ons installed).
This gun does more damage per pound of ammo than any other automatic gun on Hardcore mode, at 1184/lb.