Heckler & Koch HK GMG (GMW / GraMaWa)

History

The Heckler & Koch GMG ("GranatMaschinenWaffel" or "GraMaWa") is a 40mm automatic grenade launcher similar in form and function to the US Mk-19 series. It can fire 40x53mm high velocity shells with various warhead types to meet mission requirements. The high-speed form contrasts sharply with the 40x46mm low-speed series in several shoulder-fired weapons. The high-speed version is mainly used for vehicle-mounted cannons.

As such, the GMG is an oversized automatic grenade launcher, usually mounted on a heavy trunnion mount or tripod assembly.

Overall dimensions include 1,090mm barrel length and 415mm barrel length. The field version of the weapon consists of a 29kg weapon system and an 11kg tripod. The automatic nature of the weapon utilizes recoil-based API (Advanced Primer Ignition) recoil action, consistent with 20mm and larger firearm calibers. The API action fires the primer while the bolt is still moving (moving forward) while the cartridge is still in the chamber. The breech moves forward and back in the breech, which reduces recoil, which is great for an automatic weapon like this.

The GMG's rate of fire is 350 rounds per minute, with each shell fired at a muzzle velocity of 790 feet per second, with an effective range of 1,500 yards and a maximum attack range of 2,200 yards. The GMG is powered by a 32-round disintegration chain belt, usually stored in the included ammo box. The feed goes through the right side of the receiver, and the used case is ejected through the opening on the left. A carrying handle is attached to the bottom of the barrel, while an additional aiming handle is located at the rear of the receiver.

The barrel is closed by a long slotted muzzle brake. While it comes with standard iron sights, it also comes with reflex optical sights.

The GMG was designed by Heckler & Koch engineers between 1992 and 1995, before being adopted by the German Armed Forces in 1996. The series is still in production today (2013) and is produced in Canada (as licensed Rheinmetall-Canada "C16 CASW"), Finland (as "40 KRKK 2005"), Greece, Ireland, Latvia, Lithuania, Netherlands, New Zealand, Norway, Poland, Portugal, Slovenia, United Kingdom (known as "L134A1") and United States (part of SOCOM).

Specification

Roles

Dimensions

Performance

Changes