Underwood Ammo XTP Features Underwood Ammo builds its XTP line around Hornady s eXtreme Terminal Performance bullet chosen specifically for deep terminal penetration paired with controlled reliable expansion. In .357 Sig this 124 grain jacketed hollow point leaves the barrel at 1475 fps generating 599 ft lbs of muzzle energy for serious stopping power in a self defense scenario. The load is rated supersonic and Underwood also notes it is safe for use in a suppressor giving shooters flexibility across different firearm configurations. A ballistic coefficient of 0.118 reflects the round s design priority on terminal performance rather than extended range accuracy. Nickel plated brass casings are used throughout this load improving feeding reliability across a range of firearm actions while resisting tarnish better than traditional brass during long term storage. Underwood also loads this round with flash suppressed powder helping preserve the shooter s vision in low light conditions where a follow up shot may be necessary. Each box contains 20 rounds giving shooters a practical supply for practice or carry replenishment. Underwood Ammo field tests its loads using popular widely owned firearms ensuring this .357 Sig round performs reliably in the platforms shooters actually carry. Underwood Ammo XTP Specifications Manufacturer: Underwood Ammo Model: XTP Caliber: 357 Sig Rounds Per Box: 20 Bullet Weight: 124 gr Bullet Type: Jacketed Hollow Point Case Material: Nickel-Plated Brass Muzzle Velocity: 1475 fps Muzzle Energy: 599 ft lbs Application: Personal Defense Available At: GrabAGun