The MP5/10 is designed to meet the ever increasing call by U.S. Law Enforcement for a compact, accurate and reliable submachine gun chambered for a cartridge with increased terminal effects on target. The 10mm Auto cartridge provides up to twice the muzzle energy of the standard 9mm parabellum NATO cartridge, and still is easily controllable due to the unique roller-locked bolt system employed throughout the HK line of weapons. This perfect combination of weapon and cartridge puts the firepower, penetration and hard hitting potential of a .45 ACP Thompson SMG into a package identical in size and weight to the 9mm MP5!