M320 Grenade Launcher Module

M320 Grenade Launcher Module
Standalone M320 with detachable buttstock
Type	Grenade launcher
Place of origin	Germany
Service history
In service	2009–present
Production history
Designed	2008
Manufacturer	Heckler & Koch
Unit cost	US$3,500
Produced	2008
Specifications
Weight	1.5 kg (3.3 lb)
Length	350 mm (13.7 in.)
Barrel length	280 mm (11 in.)
Cartridge	40x46mm SR
Action	Single shot, double action
Rate of fire	5 to 7 rounds per minute
Muzzle velocity	76 m/s
Effective firing range	150 m (point) 350 m (area)
Maximum firing range	400 m
Feed system	Single shot

M320 Grenade Launcher Module (GLM) is the U.S. military's designation for a new single-shot 40 mm grenade launcher system to replace the M203 for the U.S. Army, while other services will keep using the older M203. The M320 uses the same High-Low Propulsion System as the M203.

In 2004, the Army announced a requirement for a commercial off-the-shelf 40 mm grenade launcher. It had to be more reliable, ergonomic, accurate, and safer than the M203. It had to be able to fire all 40 mm low-velocity grenades, but be loaded from the breech to accept future longer projectiles. Heckler & Koch's submission was selected in May 2005.

After the U.S. Army at Picatinny Arsenal conducted a competitive bidding process for a new 40 mm grenade launching system, Heckler & Koch was awarded a contract to provide the XM320 beginning in 2006. The M320 was developed from but is not identical to the Heckler & Koch AG36 (a key distinguishing feature being the addition of a folding foregrip ahead of the trigger for use when the weapon is in stand-alone configuration, a feature the AG36 lacks). The M320 entered production in November 2008.

Fielding of the M320 was planned to begin in February 2009, with 71,600 GLMs planned to phase out the M203 by 2015. The weapon was officially fielded in July 2009 at Fort Bragg by the 1st Brigade Combat Team, 82nd Airborne Division.

The M320 has three major parts: a grenade launcher with rifled barrel, Day/Night Sight (DNS) produced by Insight Technology, Inc and a hand held Laser Range Finder (LRF). Some of the benefits are:

The M320 is based on the earlier Heckler & Koch AG-C, but with some Army-specific modifications. It includes a folding foregrip and shorter barrel for a more compact package. The sights had to be reconfigured to shoot accurately with the slightly different ballistics from the shorter barrel length. The system was supposed to be lighter than the M203 (it is actually slightly heavier) and does not require specific mounting hardware. Breech loading allows the grenadier to load a shell while keeping the sight on target. It weighs 3.57 lb (1.62 kg) in its base configuration, 3.89 lb (1.76 kg) with the LRF and electronic sight, and 4.8 lb (2.2 kg) with the stock attached. The sights on the M320 are located to the side of the launcher, avoiding the problems that the M203 had with its sight design, which were mounted on top of the launcher and could interfere with the rifle's sights, so they had to be attached separately. This meant two separate operations had to be performed when adding the grenade launcher to the weapon, and since the sights were not integral to the M203, they had to be re-zeroed every time the launcher was reattached to the rifle. The LRF helps eliminate range estimation errors common in shots greater than 100 meters, thus increasing first round hit probability.