Abstract: A shell deflector-catcher which can be removably mounted on the receiver of a firearm adjacent to the shell ejection port therein. The device is provided with tabs which engage walls of the receiver and a springy finger which lies adjacent to the ejection port and contacts spent shells ejected therefrom to deflect the shells downwardly toward the ground. The spring finger may be fitted with a removable cap which enlarges the dimensions of the finger to enable it to cooperate with one side wall of the ejection port to catch ejected shells and prevent them from falling to the ground.