Abstract: In order to simplify manually loading cartridges into a magazine, a device is provided for use with a magazine that receives a plurality of cartridges in stacked relation through an opening against a force biasing the cartridges toward the opening. The device includes a band configured in size and shape for placement on a thumb of one hand for loading the magazine with the cartridges when the magazine is gripped by that one hand. The device also includes a projection integrally associated with the band and extending from an outer surface of the band for engagement of a top one of the cartridges previously loaded into the magazine. With this arrangement, the projection has a surface adapted to contact a surface of the cartridges in such manner as to engage the top one of the cartridges when the magazine is gripped for depressing the top one of the cartridges away from the opening against the biasing force in response to a bending/depressing thumb motion.