These two Mouth-Activated Trigger Mechanisms are designed to allow one with limited or no use of arms or hands to fire a rifle. The powered model (TM100) is a battery-operated, vacuum-actuated system, which consists of (1) a trigger-pulling mechanism that attaches to the gun's trigger guard and (2) a control box that mounts onto the stock via Velcro strap. The box includes two insulated wires-one running to the triggering mechanism, the other to an auxiliary battery-and a mouthpiece that, with slight suction, fires the weapon. The bite model (BT100) consists of (1) a trigger-pulling mechanism that attaches to the gun's trigger guard with mounting screws and (2) a mouthpiece with cable running to the mechanism that mounts onto the stock via Velcro strap; it operates by biting down on the mouthpiece.