XM320 Grenade Launcher Module And XM26 Modular Accessory Shotgun System

By Scott R. Gourley

Two new weapon systems soon to enter U.S. Army inventories will provide today’s warfighters with increased lethality, greater reliability and enhanced tactical capabilities. The new systems are the XM320 40 mm grenade launcher module (GLM) and the XM26 12-gauge modular accessory shotgun system (MASS).

The XM320 GLM will replace selected M203 series grenade launchers currently mounted on M16/M4 series rifles and carbines.

In making its May 2005 contract award announcement, Heckler & Koch Defense Inc. noted that the company’s receipt of the XM320 contract marked the completion of a full and open competition among several companies to provide a commercial off-the-shelf shoulder-fired grenade launcher that met or surpassed all user-developed requirements.

The XM320 grenade launcher module was selected after months of rigorous bid sample testing, including a user evaluation at the Army’s Aberdeen Test Center in Aberdeen, Md. The XM320 is a multifunctional single-shot launcher that can be attached to a wide range of current issue U.S. weapons, including the M16A2 and M16A4 rifles, and M4, M4A1 and M4 (modular weapon system) carbines.

According to Barbara Muldowney, U.S. Army deputy product manager for Individual Weapons (Program Executive Officer-Soldier), the XM320 provides a number of advantages over the currently fielded M203.

“Number one, it is a lighter weight system than the 203,” she explained. “It provides an open architecture system for the mounting system, so a 320 can go on an M4, M16A2, M16A4, or the ‘mod’ weapon systems, and it does not require separate mounting interfaces like the 203 does. It also has an unrestricted breech mechanism, because it opens to the side, so all current munitions [current munitions are 40 mm x 46 mm] and any future munitions that could be longer are applicable now. With the current 203, you only have a certain length breech so only certain munitions can go in there. It also converts to a stand-alone system with a separate buttstock that we will have in the supply system. Last but not least, it will be a safer and more reliable weapon because we are using a new double-action trigger and firing system.”

As an aside, Muldowney compared the tactical employment of the current M203 with that of the XM320.

“Currently, with the 203, in order for the soldier to put the munitions in, they actually have to turn over the whole system,” she said. “If it’s under an M4, for example, they have to make sure that it is upside down so that the breech is exposed. Then they put the munition in and pull the pump in so that it closes. With the XM320 they can always have their sight on the target while they put the munitions in, so they don’t have to take the two extra steps of inverting the weapon system and then turning it back over.”

HK Defense has delivered approximately 60 XM320 units for developmental testing that should begin within weeks of the publication of this issue. That will be followed by operational testing (OT), which is scheduled to occur at the end of fiscal year (FY) 2006 and run into early FY 2007. Following successful OT the program will likely move into full-rate production, dropping its X designator at that point.

Muldowney noted that the 2005 contract award for the developmental units included a couple of options for low-rate initial production and one option for full-rate production for a total quantity of approximately 10,000 weapons.

Those 10,000 systems will likely represent an initial replacement for approximately 71,000 M203s in military inventories (only about half of this total are in service at this time).
Even before formal fielding of the XM320, Army warfighters will begin receiving initial deliveries of the new XM26 12-gauge modular accessory shotgun system. Designed as an under-barrel shotgun accessory for the M116/M4/modular weapon system series, the XM26 fires standard 12-gauge munitions, including nonlethal and breaching munitions. Equipped with a five-round magazine, the single-action design requires loading each round with the cocking handle on the left side of the weapon. In addition to barrel mounting, the shotgun module is also provided with a buttstock that provides recoil mitigation when fired in a stand-alone configuration.

According to Lt. Col. Tim Chyma, product manager, Individual Weapons, Program Executive Office-Soldier, the XM26 program is in response to urgent user requirements to have a shotgun system for infantry soldiers, military police and other units. In door-breaching operations, these units were required to carry stand-alone shotguns, essentially adding another weapon requirement to the warfighter. The development of a shotgun accessory eliminates the second weapon requirement. The availability of the stand-alone buttstock, however, still allows that tactical flexibility when and if it is desired.

Those urgent requirements led to a developmental lightweight shotgun system (LSS). In July 2003 the Army accepted delivery of approximately 200 LSS units for urgent materiel release to battlelabs for testing.

The systems were subsequently fielded to 10th Mountain Division (Light Infantry) units in Kandahar and Bagram in Afghanistan in November of that year.

Based on field experience in Afghanistan, those Army elements provided concept and design assessments of the developmental systems.

Chyma noted that the suggested design changes to the operating system primarily focused on reliability and ergonomics. One readily evident change can be seen in a new XM26 muzzle design, which incorporates a spring device that allows the muzzle to be pulled forward and locked into an extended position. The extended configuration provides a built-in standoff distance that provides optimum effectiveness against door hinges or bolts during door-breaching operations.

“That design came from feedback from soldiers in the field,” Chyma said, adding that the changes were incorporated through a program down-select with a contract award to C-More Systems during the summer of 2005.

Reiterating the system’s warfighter focus, Chyma summarized, “The features of the XM26 that are beneficial to the warfighter include a modular design that allows easy mounting to the M4 or M16. Since it is modular, it can be stowed in the warfighters’ rucksack until needed. In addition to quickly and easily mounting to the M4 or M16, it can also be fired in a stand-alone configuration. It fires standard 12-gauge lethal and nonlethal munitions and has an integral standoff feature that can be used when door breaching.”

XM26 operational testing is expected to begin this month with follow-on fielding projected for late summer.