Remington Premier Magnum Rimfire 17 HMR 20gr PSP Rimfire Ammo - 50 Rounds - Looking for a rimfire cartridge with a centerfire attitude? Remington's got you covered with the complete line of Magnum Rimfire ammunition. This ammunition is loaded for incredible shot-to-shot consistency, flat trajectory and explosive expansion. Upgrading your rimfire rifle or handgun is as easy as shooting the right ammo. Think Magnum Rimfire.