Heckler and Koch HK417 German 7.62mm Battle Rifle

The Heckler & Koch HK417 is a battle rifle, designed and manufactured by Heckler & Koch in Germany. It is the larger caliber version of the HK416 and chambered for the 7.62×51mm NATO rifle cartridge. It is a gas-operated, selective-fire rifle with a rotating bolt. The HK417 is intended for use in roles where the penetrative power, stopping power, and range of the 7.62×51mm cartridge are required. It has been adopted for service by a number of armed forces, special forces, and police organizations. The HK417 is similar in internal design to the HK416, although the receiver and working parts are enlarged to suit the larger 7.62×51mm cartridge. The bolt is a seven-lug rotating type, which sits in a bolt carrier and operates in a forged alloy receiver resembling those of the Stoner-designed AR-10, AR-15, and M16 rifles. Like the HK416, the HK417 is gas-operated with a short-stroke piston design similar to that of the Heckler & Koch G36. The short-stroke piston is more reliable than the original direct impingement operation of the AR-15 design because, unlike these weapons, it does not vent propellant gases directly into the receiver, which deposits carbon fouling onto the bolt mechanism as well as heating it up. The early HK417 prototype used 20-round magazines from the Heckler & Koch G3 rifle family, which did not feature a bolt hold-open device. Later prototypes, however, switched to a polymer magazine with bolt hold-open. The magazine resembles an enlarged version of the G36's transparent magazine, except without the pins for holding more than one magazine together.