Engineered to maximize terminal ballistics as defined by FBI test protocol Defender ammunition provides maximum stopping power for the ultimate in personal defense. Winchester’s innovative bonding process welds the jacket to lead core for improved penetration 1.5x expansion and the proven performance you rely on when the stakes are high. – Caliber: 10mm Auto – Bullet Type: Bonded Jacket Hollow Point – Bullet Weight: 180 gr – Muzzle Energy: 614 ft / lbs – Muzzle Velocity: 1240 fps – Rounds Per Box: 20