Federal Power-Shok is hard hitting ammunition designed for exceptional performance in the field. A combination of premium bullets with Federal's reputation for quality results in a hunting round that you can depend on. This ammunition is new production, non-corrosive, in boxer primed, reloadable brass cases. What Mauser Ammo and Reloading Components do I need?MidwayUSA carries JS and JRS 8x57mm (8mm Mauser) ammunition and brass. The standard 8x57mm JS Mauser is by far the most common version of this cartridge, used in military and sporting bolt action rifles. The less-common JRS Mauser is a rimmed cartridge developed for double barrel rifles. If you have a bolt action 8mm Mauser, you will want 8x57mm JS Mauser ammunition and components.