Based on the SWD/Cobray Street Sweeper, the Assault Shotgun is a fully automatic, 8 shells per magazine shotgun capable of very rapid successions of gunfire that allows for very easy destruction of vehicles (even low-flying helicopters) and quick kills. The gun features a stock, but is constantly depicted folded.
The weapon first entered prominence in the mission "Heavy Toll" when Johnny Klebitz, along with Malc and DeSean, stop a convoy and steals a van full of cocaine using the gun. The shotgun is also featured during the chase sequence in "Shifting Weight", when the player is required to defend Malc and DeSean from the pursuing police using the gun, which is capable of pumping out unlimited rounds during the course of the chase.
The Assault Shotgun can be purchased from Terry's gun van after completing "Heavy Toll" and will spawn at the player's safehouses after completion of 40 gang wars (though it will not begin spawning until "Heavy Toll" has been completed).
- Although the Assault Shotgun is based on the Street Sweeper, the Street Sweeper is actually semi-automatic only and cannot fire in fully-automatic like shown in-game. The Assault Shotgun behaves similarly to the AA-12, a full-auto shotgun featured in The Ballad of Gay Tony as the "Auto Shotgun".
- If the player blind fires with the shotgun he will be seen pumping the gun after every shot is fired, even though it is fully automatic. This also limits the blindfiring speed to the Pump Action Shotgun as it uses the same animation. The Combat Shotgun and the Automatic Shotgun also have this problem.
- Similarly, when it is being reloaded, Johnny or the multiplayer character will be seen removing the magazine. In reality, the Cobray Street Sweeper's magazine is fixed to the gun and each shell must be loaded individually into it.
- In "Heavy Toll", Johnny refers to the shotgun as "an American firearm". He is only partially correct, because the Street Sweeper is a copy of the South African Armsel Striker produced under license in America by the Cobray Company.
- Real Cobray Street Sweepers have ten or twelve round drum magazines and are semi-automatic, while the one featured in the game has an 8 round drum and is incorrectly portrayed as being fully automatic with an extremely high rate of fire.