Abstract: A magazine for a rimfire adapter to feed cartridges into a rifle in which e cartridges are shorter than those for which the rifle was intended. The magazine cavity is positioned rearwardly, in order for the base of the shorter cartridges to be positioned longitudinally in the same position the original cartridge would have been if it were used. This overcomes the double firing safety hazard while suitable ramps and guides are positioned forwardly to guide cartridge travel forward to the chamber.

Abstract: A conversion system is disclosed for adapting a rifle to fire ammunition of ifferent shape or type than that for which the rifle was designed. The conversion system includes a modified bolt with suitable supports for mounting the same in a rifle receiver in place of the standard rifle bolt. A novel magazine is included for cooperative action with the modified bolt to assure accurate feeding of the different ammunition. Safety features such as prevention of double firing and open bolt retention for inspection after firing the last round is emphasized. Bolt carrier travel on recoil to insure cocking is less than that required to feed the next round into the chamber to prevent double firing. A vertical surface on the bolt engages the rifle's bolt catch to hold the bolt out of battery for visual inspection of the rear of the rifle chamber.