Ordnance Notes -- by Bob Stoner

Ordnance Notes -- by Bob Stoner GMCM (SW) Ret.

XM203 40mm Grenade Launcher

An M16A1 rifle with the M203 grenade launcher attached. Note the distinctive hand guard for the rifle and the battle sight for the M203 (folded, in back of the rifle's front sight) and that the rifle's front sling swivel has been repositioned to the side. The indirect fire sight for the M203 is attached to the rifle's carrying handle. The barrel release lever is the prominent tab above the serrated guard for the M203's barrel. The safety for the launcher is located ahead of the launcher's trigger. The photo shows the safety in the ON (SAFE) position. The trigger guard of the M203 is designed to open, in a manner similar to the trigger guard of the rifle, to allow the firing of grenades in cold weather conditions when mittens are used. (Photo: Pattern Room Enfield)

Aircraft Armaments, Inc. (AAI) was the second contractor in the grenade launcher race (Colt’s Firearms was the other). AAI was also the prime contractor for the SPIW and they investigated many different grenade launcher concepts that used the 40mm grenade of the M79 and a smaller 30mm AAI design. Various launchers were tried: a disposable barrel, encapsulated grenade, a 3-shot manually operated launcher with either a straight line feed or rotary magazine, a 3-shot semi-automatic launcher, and a simple single-shot launcher whose barrel pulled forward to load.

An M203 grenade launcher and its handguard with battle sight for the M16 rifle. (Photo: Colt Firearms)

A Navy SEAL with a XM177E2 submachine gun and M203 grenade launcher attached. The AAI M203 was far superior to the Colt XM148 design. It rapidly replaced the XM148 in Naval Special Warfare and the U.S. Armed Forces. (Photo: MilitaryPhotos.net)

The AAI design was standardized as the M203 40mm grenade launcher and has mostly replaced the M79 break-action launcher. The adoption of the M16 and M203 combination allowed the grenadier in the squad to carry a rifle comparable to his buddies and allowed him to dispense with the short-ranged pistol as his only other offensive weapon. The photo shows an M16A1 5.56mm rifle with the M203 40mm grenade launcher, the new hand guards which mount the battle sight for the M203, and the indirect fire sight (attached to the carrying handle of the rifle). The M203 can also be attached to the M16A2 5.56mm rifle and M4 5.56mm carbine.

The M4-series carbines are the M16A2 rifle with a shortened barrel and telescoping butt stock similar to the XM177-series 5.56mm submachine guns. Today's SEAL grenadier may use either the M16A2 or the M4 with the M203 attached. Due to its size and weight, the M4/M203 combination is the preferred combination for military operations in urban terrain (MOUT).

SEAL units prefer the Colt M4A1 carbine with M203 grenade launcher attached. This M4A1 has both an indirect fire (mounted on the carrying handle) and a short range battle sight (on top of handguard).. (Photo: Colt Firearms)

An illustration from the Army M203 manual showing the loading and firing sequence for the M203. Opening the barrel (1); loading the grenade in the barrel (2); closing the barrel before firing (3).