Hornady's Superformance uses progressive propellants that take your favorite V-MAX, NTX, SST, GMX, InterLock, and InterBond bullets to levels of performance that are simply unattainable with conventional ammunition. It use the highest quality cases and primers available which equals consistent components that translates to consistent shooting in the field. The Superformance ammunition is 100 to 200 fps faster than conventional ammunition and is safe for use in all firearm types, including semi-autos, lever guns and pump actions. This 300 Winchester Short Magnum (WSM) load features a GMX bullet with a 165 grain weight and comes packaged 20 rounds per box, 10 boxes per case.