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The United States Army ended the Great War with the French-designed V-B rifle grenade launcher as standard. The V-B utilized a cup type launcher fitted to the on the M-1903/M-1917 rifle. The V-B grenade had a hole through the middle which allowed the use of standard rifle ammunition. The bullet passed through the hole and the gas generated by firing propelled the grenade to a maximum range of 200 yards.

While the V-B launcher saw wide-spread use during World War One, there were problems. The loose fit between the launcher and the rifle often caused inaccuracy and loss of range. In addition, manufacturing errors sometimes resulted in V-B grenades with off-center holes and premature explosions could result.

The V-B launcher remained in U.S. service until 1924, when it was restricted to firing pyrotechnic shells and it was declared obsolete in 1928.

Work on a replacement for the V-B continued at a snail’s pace during the 1930s, mainly due to elements in the Army that disputed the need for a rifle grenade launcher. By 1940, the war raging in Europe confirmed the need to propel grenades for loner distances than hand throwing. Early experiments with the M-1 Garand resulted in numerous failures and the decision was made to design a grenade launcher for use with the service bolt-action rifles.

The M-1 Grenade Launcher/The M-2 Grenade Launcher
Adopted in 1941, the M-1 launcher was designed for the M-1903 rifle while the M-2 was designed for the M-1917 rifle. Both clamped to the end of the barrel by means of a clamp secured by a wing nut. The tube was about 7.25-inches long and weighed 9 ounces. The tube had a series of raised rings on the outside surface which were used in conjunction with the angle of elevation to determine range. With a grenade in place on the tube, the greater number of rings exposed, the shorter the range. A special grenade cartridge was used to fire the grenade. Both launchers could be easily removed and then allow the firing of normal ball ammunition.

The initial production concentrated on the M-2 launcher due to the decision to transfer large numbers of the M-1917 rifle to the United Kingdom as part of Lend-Lease (some 31,980 prior to December 1941). With the entry of the U.S. into the war on December 8, 1941, the War Department ordered a switch in production to the M-1 launcher. Production of some 63,360 in January 1942 and another 55,040 in February met the U.S. Army’s foreseeable needs and production was shifted back to the M-2 launcher. The last of the M-2s rolled off the production line in July 1942 with some 112,327 completed. Production shifted back the M-1 launcher until May of 1943, when some 322,892 were completed (and a further 39,793 M-2 were converted into M-1s).

In U.S. service, the M-2 was mostly used for training and practice. The M-2 was declared obsolete of in September 1944.

The M-1 Launcher remained in service throughout the war for two reasons: first the M-1 Garand Rifle was in short supply prior to mid-to-late 1943, so the M-1903 was often the only rifle available to many troops. Secondly, the problems encountered with developing a satisfactory grenade launcher for the Garand was never solved during the war. A launcher was eventually adopted, but the rifle could not fire service ammunition with the launcher fitted. Even when production of the Garand caught up to demand, many soldiers preferred the M-1903/M-1.

The M-7 Grenade Launcher
While the M-1 and M-2 Launchers were in production, development was underway for a launcher that could be used with the semiautomatic M-1 Garand rifle. A number of developmental models were tested before the T14 was standardized as the M-7 in February, 1843. The M-7 clamped the M-1 rifle’s bayonet lug by a hinged clamp and had a stud that fitted into the rifle’s gas cylinder valve screw to hold it open and vent excess gas. This prevented the M-1 rifle from operating in the normal semiautomatic mode with the grenade launcher attached. A special type of valve screw was issued with each M-7 along with an instruction sheet. The original type of screw (B147851) remained open after the launcher was removed and closed after a live round was fired. A improved version (B7310079) was adopted in January 1945 which closed immediately upon the launcher being removed from the rifle. The special valve screw was necessary in order to “bleed off” the excess gas generated by the grenade launching cartridge that would otherwise wither blown up or otherwise seriously damaged the rifle.

Total production of the M-7 came to be some 795,699 by August 1945.

The M-7 worked reasonably well, but had the unpopular handicap of not allowing the M-1 rifle to fire in the semiautomatic mode with the launcher attached. Since the soldier would not want to keep the launcher attached to his rifle any longer than necessary, they typical employment method became to fire the grenade and then quickly remove the launcher so that the rifle could be fired immediately. This led to large numbers of the M-7 being dropped in the heat of battle and not being retrieved later. The high production numbers reflect as the War Department tried to keep up with combat losses.

An improved M-7A1 launcher was developed in July of 1945. This was functionally similar to the M-7 but had the advantage of allowing the M-1 rifle to fire normally while the launcher was in place. A total of 72,000 were produced by August 1945, but were never issued.

M-8 Grenade Launcher
While work was underway on the M-7 launcher for the M-1 rifle, a launcher was being developed for use with the M-1 carbine. While the carbine was never intended for use with a grenade launcher, the problems with the M-1 rifle’s launcher gave urgency to the development of one for the carbine.

The carbine’s gas system actually made the design of a suitable grenade launcher much easier than for the Garand. A launcher, very similar to the M-1 and M-2 launchers that clamped to the end of the barrel (and held in place by a wing nut) was developed. Since the venting of excess gas was not necessary, the carbine could function in the semiautomatic mode with the launcher in place.

The carbine grenade launcher was standardized as the M-8 in February of 1943. A total of 385,165 were produced by August 1945. While the M-8 proved to be popular with the troops, the M-1 carbine had never been intended to withstand the stresses of firing a rifle grenade, split or broken stocks were common. The M-1A1 carbine could only be used to fire a rifle grenade by folding the stock, pointing the pistol grip upwards, with the rear of the stock firmly on the ground, even doing this still left a chance of the stock being bent under the force of firing.

Grenade Launching Ammunition
In order to launch rifle grenades, special ammunition was needed that could develop sufficient gasses to propel the rifle grenade. Grenade launcher ammunition looked somewhat like blank ammunition, but could be identified by their crimped necks.

Cartridge, Rifle Grenade, Caliber .30, M-3
The M-1, M-2 and M-7 launchers utilized the M-3 grenade cartridge to launch rifle grenades. The M-3 was loaded with five grains of very fine black powder and 40 grains of smokeless powder. This load could propel the standard M-9A1 antitank grenade with a velocity of 180 feet per second. The M-3 cartridge was issued in ten round cartons.

Cartridge, Rifle Grenade, Carbine, Caliber .30, M-6
The carbine’s M-8 launcher was used with the M-6 grenade launching cartridge. This round was loaded with one grain of 60mm mortar ignition powder and 20 grains of smokeless powder. This could propel the M-1 grenade adapter at a velocity of 145 feet per second. The M-6 cartridge was packed in cartons holding six rounds.

Cartridge, Grenade, Auxiliary, M-7
In order to increase the range of a rifle grenade, a auxiliary cartridge was developed. This small cartridge could be inserted into the grenade launcher tube prior to placing a grenade on it and was ignited by the firing of the grenade cartridge. The use of the M-7 increased the velocity of the grenade by 40-90 feet per second and increased the range by 60-100 yards. Since the use of M-7 markedly increased the recoil, its use in the carbine was restricted to emergencies only. The M-7 quickly gained the nickname of “the vitamin pill”.

Rifle Grenades
There were two basic types of rifle grenades. The first consisted of adapters that held a standard hand grenade. The second consisted of grenades specifically designed as rifle grenades.

M-1 and M-1A1 Grenade Projection Adapters
The M-1 Grenade Projection Adapter was designed to hold a standard Mark II fragmentation hand grenade. It secured the grenade by means of four retaining claws that grasped the grenade’s serrations. One of the claws also mounted a metal arming clip into which the grenade’s safety lever was fitted and held in place (the M-1A1 was similar, but used only three claws). Both adapters were about seven inches in length.

The adapters were simple and effective in their use. The Mark II grenade was inserted into the adapter and the safety lever inserted into the arming clip. The grenade’s safety pin was pulled (but the arming clip held the safety lever securely in place). When the grenade was fired from the launcher, the arming clip was sheared away, thus releasing the safety lever. The timing fuse then exploded the grenade. By using the adapter, the Mark II could be used to inflict enemy casualties by effective air bursts.

Due to the heavy recoil generated by the rifle grenade and the fact that a curved trajectory was usually the most effective, the butt of the rifle was placed on the ground for firing. Regulations called for the rifle grenade to be launched with “…the butt turned sideways to avoid stock breakage.”

The M-1 and M-1A1 adapters saw much use during the war. With practice, a soldier could fire fragmentation grenades with surprising accuracy for a distance of almost 200 yards.

Chemical Grenade Adapter, M-2 and M-2A1
Similar in use to the M-1 and M-1A1, the M-2 adapters were used to fire the colored smoke, offensive and white phosphorous grenades. Both the M-2 and M-2A1 were fitted with three claws and a retaining band, they differed only in the fin assembly fitted.

Functionally, they were used in the same manner as the M-1/M-aA1 adapters.

M-17 Impact Fragmentation Rifle Grenade
The only other type of fragmentation grenade launched from grenade launchers was the M-17. This consisted of a fragmentation grenade similar to the Mark II, but fitted with an impact fuse. The M-17 was designed strictly as a rifle grenade . Due to the inherent dangers of an impact use, few were made and issued.

M-9 and M-9A1 Antitank Rifle Grenade
The M-9 was issued in the early days of the war and was quickly replaced by the M-9A1. The M-9A1 had a sheet metal body and nose that contained a shaped charge similar to that used in the bazooka. The grenade was fitted with an impact fuse and had a safety pin that had to be removed prior to firing. The M-9A1 could penetrate between 3-4 inches of armor. It weighed 1.31 pounds and had a maximum effective range of 250 yards.

The M-9A1 was a simple and effective weapons. The grenade would be fitted onto the launcher at the desired range increment. A safety fin would be removed prior to firing. Unlike the frag and chemical grenades, it was necessary to fire the M-9A1 using a flat trajectory. This meant that the soldier would have to fire the weapon from the shoulder rather than placing the butt on the ground to absorb the heavy recoil.

M-19 White Phosphorus Rifle Grenade
Similar in appearance to the M-9A1, the M-19 had a filler of white phosphorus. Upon impact, it would scatter WP pellets over an area of about 10 yards, igniting spontaneously and giving off a dense white smoke as well as inflicting casualties.

M-22 Colored Smoke Rifle Grenade
The standard colored smoke grenade of World War II. Produced in four colors: red, green, violet and yellow. Fitted with an impact fuse. The M-22 was used for signaling as well as marking targets.

M-23 Colored Smoke Rifle Grenade
Once fired, the M-23 would ignite, leaving a streamer of smoke that lasted roughly 12 seconds, this continuous stream of smoke would burn throughout its 250 yard range. Produced in the same four colors as the M-23.

M-20 HC Smoke Rifle Grenade
Identical to the M-22 grenade in appearance, the chief difference was that the M-20 would produce a cloud of white smoke for about 30 seconds upon impact. As with the An-M8 HC Smoke grenade, the purpose of the M-20 was to conceal troop movements.

M-17A1 Ground Signal, White Star, Parachute Rifle Grenade
M-18A1 Ground Signal, Green Star, Parachute Rifle Grenade
M-21A1Ground Signal, Amber Star, Parachute Rifle Grenade
M-15A1 Ground Signal, Red Star, Parachute Rifle Grenade
This series contained a parachute flare that separated from the case at about 400 feet in the air. It would burn for about 30 seconds and was used for illumination purposes as well as signaling

M-8A1 Ground Signal, White Star, Cluster Rifle Grenade
M-20A1 Ground Signal, Green Star, Cluster Rifle Grenade
M-22A1 Ground Signal, Amber Star, Cluster Rifle Grenade
M-52A1 Ground Signal, Red Star, Cluster Rifle Grenade
This series was used in the same manner as the parachute flares, but contained five pyrotechnic stars that were ejected from the case at about 400 feet and burned for five seconds.

Grenade Launching Sights
Sight, Rifle, Grenade Launcher M-1
In order to improve the accuracy of rifle grenades, several types of auxiliary sights were tested during the war. The first to be standardized was the M-1 sight, designed for use with the M1903 and M1917 service rifles. This was a rather crude sight constructed of two stamped sheet metal front and rear sights that were aligned to achieve the required angle of elevation. The two sight components were fastened to the rifle by springs and attached together by a wire spacer.

The M-1 sight saw very limited use early in the war and proved to be unsatisfactory. It was soon dropped from use.

Sight, Rifle Grenade, M-15
With the failure of the M-1 sight, several other sights were tested with varying degrees of success. The best design was the T59E3, which featured a sighting bar with a leveling bubble and a front post and rear peep sight. The T95E3 could be used with the M1903 and M1 rifles and M1 carbine. A mounting plate was installed on the weapon’s stock by two screws. The sight assembly was attached to the mounting plate and could be elevated or depressed from zero to sixty degrees. The T95E3 was standardized as the M-15 in March of 1944 and some 20,000 were produced.

The M-15 could be used to launch antitank rifle grenades with the peep sight and fragmentation and smoke grenades with the bubble sight.

Recoil Boot
The last item used with grenade launchers was a black rubber recoil boot. The boot slipped onto the butt of the rifle and contained a thick rubber pad. It could be used with the service rifles, but could not fit the carbine stock. It was designed to help cushion the heavy recoil of the rifle grenade when fired from the shoulder. It also lessened the chances of the stock breaking when the butt of the rifle was placed on the ground.