Hornady Handgun Hunter ammunition is built around a bullet as rough and rugged as the conditions and game demand. The MonoFlex handgun projectile is manufactured with a tough copper alloy that achieves deep penetration and 95% weight retention. Bullet expansion across a range of velocities is aided with an elastomer material added to the bullet s open cavity. Upon impact, the elastomer compresses, then pushes out and causes the bullet to expand faster than a standard hollow point design. Combined with premium cases, primers and propellants, Handgun Hunter ammunition benefits from years of producing hard-hitting GMX and MonoFlex rifle bullets to introduce a handgun version that lives up to our reputation. Product Features MONOFLEX Bullet Technology: The tough copper alloy in the MonoFlex bullet allows for deep penetration while retaining 95% of its weight for maximum impact. Elastomer Material: An elastomer material in the bullet s open cavity compresses upon impact and then pushes out, causing rapid expansion. Premium Components: Premium cases, primers and propellants combine with the MonoFlex bullet to create a cartridge that delivers superior performance in the field. Product Specifications Caliber: 10mm Bullet Weight: 135 gr Bullet Type: Monoflex Muzzle Velocity: 1315 fps Muzzle Energy: 518 ft-lbs Quantity: 20 Rounds per box