Hornady Critical Defense Ammunition for the 410 was purpose built for defensive handgun use and is designed to deliver maximum energy and reliable and controlled expansion regardless of the target every time. Critical Defense 410 ammunition is loaded with a 41 caliber FTX slug which has a soft polymer insert that delivers superior controlled expansion and large, deep wound cavities over a wide range of velocities, this slug is designed to engage the rifling of the pistol so the nose of the slug will engage the target nose-on. Underneath the slug are two 35 caliber high antimony lead round balls which resist deformation and provide enhanced penetration.