Underwood Ammo Handgun Ammunition Features The Underwood Ammo Handgun Ammunition .357 Sig load is built around a 90 grain Xtreme Defender bullet machined from solid copper a lightweight design that Underwood pushes to high velocity for aggressive expansion and rapid energy dump on target. Because the bullet is a single piece of copper rather than a jacketed lead core there is no risk of core-jacket separation so the bullet holds together through barriers and tissue alike. The .357 Sig cartridge s bottlenecked case design is already known for delivering flat trajectories and strong muzzle velocities and Underwood s loading takes full advantage of that platform. This combination makes the round well suited to shooters who prioritize penetration and reliable expansion in a defensive handgun cartridge. Each box contains 20 rounds giving shooters enough ammunition to train with and still carry a full magazine s worth for personal protection. The .357 Sig has earned a following among law enforcement and civilian shooters for its combination of 9mm-like capacity platforms with significantly more velocity and energy. Reliable cycling through semi-automatic pistols chambered in .357 Sig makes this load a practical choice for duty and concealed carry use alike. This Underwood .357 Sig 90 grain copper solid load is available for sale at GrabAGun for shooters who demand top-tier defensive performance. Underwood Ammo Handgun Ammunition Specifications Manufacturer: Underwood Ammo Model: Handgun Ammunition Caliber: .357 Sig Bullet Type: Copper Solid Bullet Weight: 90 Grains Rounds Per Box: 20 Available At: GrabAGun