October 20, 2011: U.S. soldiers and marines are using a new magazine for the 40mm grenades they fire from their single shot M203 and M320 grenade launchers. The MAG-D looks like a large rifle magazine. It is spring loaded and holds five 40mm rounds. Troops can easily pull a 40mm grenade from the MAG-D and load it into their weapon. A loaded MAG-D weighs less than three kg (6.6 pounds) each and is designed to hang from the webbing of the protective vest, and make additional rounds quickly available to troops carrying a rifle with a M203 or M320 attached (under the barrel). In the past, the 40mm rounds were carried loose or in bandoliers, and often got dirty or damaged. MAG-D also eliminates confusion about where different types of 40mm grenades are (high explosive, flare, smoke, tear gas, fuel-air explosive). U.S. Marines were the first to use MAG-D (which was invented by a former marine) and want more of them.

Meanwhile, the U.S. Army has replaced the M203 40mm grenade launcher with the new M320, while the marines are still using the M203. Both launchers fit under the barrel of the M16 rifle (and similar weapons), and have been in use for forty years. The army bought 71,000 M320s (for about $3,500 each) to replace the 50,000 M203s it was using. The M320 is similar to the M203, but easier to use, has its own pistol grip, is more accurate and can be used separately from an M16 with the addition of a stock.

The biggest improvement with the M320 is its sighting system, which features a laser range finder. At night, an infrared range finder enables a soldier wearing night vision goggles to see the light beam. In over a year of testing, the M320s sighting system was seen to make the weapon much more accurate than the older M203. This was particularly the case with new users. With the M203, you got better after you had fired a hundred or so rounds. That took time, and was expensive (the 40mm grenades cost about $28 each). The 40mm grenades weigh 543 grams (19 ounces) each and have a range of about 400 meters. The grenade explosion can kill within five meters, and wound up to ten meters or more.

The marines also use the M32, a six round 40mm grenade launcher. It looks like a cross between a shotgun and a revolver type pistol. Most marine units are equipped with the M203, usually two or three per squad.