G9’s First Response uses the Armor Piercing Cavitator (APC) technology and is an extremely capable barrier round. Although this design does not expand, it uses hydraulic forces to enlarge the wound and destroy tissue by focusing high velocity castoff. This dynamic could be visualized as similar to a water jet that is able to cut through steel. The First Response has little to no deflection in auto glass. Although the muzzle velocity and energy are extremely high for the caliber, this round has reduced felt recoil due to its lower inertia.