A holder for releasable securement of cartridges in condition for simultaneous loading of the cartridges into the chambers of a revolver's cylinder. The holder comprises a cylindrical body having a plurality of axially extending, radially distributed cartridge-receiving bores adapted to align with and introduce the rounds into the revolver's cylinder chambers. The holder also includes a manually operated cartridge engagement member for axial and rotary movement within the holder body centrally of the bores and having a double star sprocket system whose lateral projections releasably lock each cartridge flange while laterally supporting each cartridge body within the holder in a position of parallelism with a center bore. The holder further includes protected means for releasing the double star sprocket system and thereby releasing the cartridges, when the cartridge ends are in the revolver's cylinder chambers, in response to the pressing of the holder against the rear of the revolver cylinder.