The Xtreme Defender is based on the popular Xtreme Penetrator product line. The XD ammunition has an optimized nose flute, total weight, and velocity to achieve a penetration depth up to 18 inches* with a permanent wound cavity (PWC) that is just simply enormous; no other expanding hollowpoint comes close to achieving anywhere near this diameter and volume. Not only is the PWC over 100% larger than any other expanding bullet, expansion is achieved despite being shot through barriers. The solid copper body ensures that wallboard, sheet metal, and automotive glass will have no effect on the Permanent Wound Channel, Falling within FBI guidelines. As with all of Underwood Ammo rounds, they utilize flash suppressed powder so that your vision will not be compromised if it becomes necessary to use your firearm in low light. While taking advantage of our state of the art testing equipment, this high-performance ammunition is field tested using popular, real firearms that our customers are most likely to own out in the real world with all the elements you would experience. This ammunition is new production, non-corrosive, in boxer primed, reloadable brass cases. A permanent wound cavity (PWC)that is 2x greater than any expanding bullet Reduced recoil Radial flutes that force the hydraulic energy inward to build pressure Minimal surface area to increase the force at the point of contact and sharp cutting edges that defeat barriers.