Corbon Ammo Deep Penetrating X bullet, Subsonic, 300 Blackout, 200 Grain, Expanding Solid Copper Hollow Point, Box of 20 Rounds DPX300AAC200 CORBON's DPX tactical rifle ammunition exhibits performance superior to all other defensive rifle ammunition on the market. "Barrier blind" is the terminology for ammunition that performs well after penetrating a heavy barrier like auto glass or steel. DPX is the only ammunition that maintains 100% of its weight after going through such barriers. The reason is the homogenous solid copper projectiles CORBON uses in these loads.