Hornady Superformance International Ammunition 308 Winchester 150 Grain GMX (20pk)Copper Alloy Construction One piece copper alloy wont separate and delivers devastating terminal performance, deep penetration and 95% weight retention. Crimping Cannelure and Pressure Relieving Grooves Reduces both bearing surface and fouling, and aids in consistent reloads. High Weight Retention High weight retention is a significant benefit to the GMX and monolithic family of bullets, routinely retaining 95% or more of their original weight. Muzzle