The Armsel Striker (also known as Sentinel Arms Co Striker-12, Protecta, Protecta Bulldog, and Cobray/SWD Street Sweeper) is a revolver 12-gauge shotgun designed for riot control and combat.

The weapon's action is similar to that of a revolver, using a rotating magazine. Since the Striker uses a more or less conventional double action only trigger, and a very large and heavy cylinder (compared to handguns), Walker added a pre-wound clock-work spring to revolve the magazine. This proved to be a slow and ineffective way to load the weapon. The design was changed so that there is now a cocking lever on the right side of the barrel.

The first designs were criticized as having a slow and cumbersome firing mechanism. The latest version has a pump-action style lever used to clear the chamber as other pump-action shotguns do. The Striker is somewhat unique for a shotgun because of its twelve round capacity and short overall length.