The latest addition to this field is the Catalyst Arms Mag Release Extension for the RPR. Rather than being molded from plastic, it’s machined from 6061-T6 aluminum, with all corners and edges nicely relieved and then hard-coat anodized. Installation is a snap — the stock mag release fits snugly into a machined slot in the back of the Catalyst Arms extension, and a small machine screw (with a drop of Loctite for good measure) holds it in place.