Underwood Ammo Xtreme Penetrator Features The Underwood Ammo Xtreme Penetrator in .357 Mag combines Underwood s trademark power with Lehigh Defense s Xtreme Penetrator bullet design which means the solid copper projectile is precision CNC machined to maximize penetration rather than relying on expansion. Its unique nose shape increases hydraulic velocity creating high pressure spikes that generate a larger permanent wound column and more than twice the penetration seen from many expanding bullets. A blunt nose aids initial energy transfer while maintaining straight deep penetration and the bullet s profile is shaped for reliable feeding through revolvers and compatible platforms. Being solid copper rather than a lead core design the bullet is completely lead free which is good for the environment while remaining tough on the target. Loaded to 1550 fps this 140 grain .357 Mag round generates 747 ft lbs of muzzle energy delivering significant stopping power for a round in this caliber class. The cutting edges on the bullet s nose allow it to punch through entry barriers without deformation or deflection maintaining a straight path to the target. Housed in nickel-plated brass casing the ammunition offers corrosion resistance and smooth chambering across a range of revolvers chambered in .357 Mag. With a sectional density of 0.16 the Xtreme Penetrator is well suited to medium to large game hunting as well as demanding personal protection scenarios. Underwood Ammo Xtreme Penetrator Specifications Manufacturer: Underwood Ammo Model: Xtreme Penetrator Caliber: .357 Mag Rounds Per Box: 20 Casing Material: Nickel-Plated Brass Muzzle Energy: 747 ft lbs Muzzle Velocity: 1550 fps Application: Medium-Large Game Bullet Weight: 140 gr Bullet Type: Solid Monolithic Sectional Density: 0.16 Rating: Supersonic Available At: GrabAGun