The NEW Matrix Inertia Semi-Auto from TriStar is a blend of beauty and function. The first Inertia driven action in the line, this Matrix is offered in Wood configuration. The Inertia system allows for a slightly broader range of ammunition, as well as less cleaning and lubrication. Inertia operated semi-automatic. Bolt remains open after last round is fired. If magazine and chamber are both loaded, opening action will result in ejecting shell from chamber but will not cycling new shell from magazine into the chamber. Magazine cut-off is located in front of trigger guard below the elevator and must be pushed to eject shell from magazine. This allows shooter to clear chamber but keep magazine loaded. CHAMBER 20GA 3" CHOKES - Imp cylinder, Modified, Full LENGTH OF PULL 14.25"