The M3 grease gun exists because the U.S. government wanted to economize how it fought World War 2.

Guns of World War 1 were often manufactured from machined parts making them expensive and time consuming to produce. At the dawn of World War 2, as countries were scaling up, they needed to do it quickly and on budget. The United States Army saw the Thompson Submachine Gun as too expensive and too complicated to make, so the Ordnance Department sought a cheap, nee – less expensive submachine gun. What it got was the M3, and with modifications, the M3A1, better known by its blue collar nickname, the Grease Gun.

Film legend Lee Marvin as Major John Reisman holds a M3 Grease Gun in the 1967 film, “The Dirty Dozen.”

M3 Grease Gun Beginnings

During World War 1, battle rifles were too long and unwieldy for trench warfare, and light machine guns lacked mobility. Soldiers often turned to pistols, grenades and knives in close combat.

Military leaders realized a rapid fire weapon would be valuable for close combat and started by trying to modify semi-automatic pistols like Germany’s M96 Mauser and Luger, but these guns were too light and had too high a rate of fire to be accurate.

Though Italy’s Villar Perosa was the first submachine gun, adopted in 1915, the dual mounted guns weren’t highly mobile. The first submachine gun people often think of is the MP 18 that Germany introduced shortly before the end of the war that fired 9mm Luger rounds. MP stood for “machschenpistole.” It was also referred to as the Kugelspritz or “bullet squirter.”

This World War 1 era German MP 18 by Theodor Bergmann appeared in early 1918 and was one of the first submachine guns to fire pistol caliber cartridges. Rock Island Auction Company sold this MP 18 in 2020 for $25,875.

The Thompson submachine didn’t come about until after World War 1, so its influence was limited to introducing the term “submachine gun.” It was sold commercially but was too heavy and expensive to be widely used, mostly ending up in police arsenals and in the hands of criminals. The United States eventually adopted it as the M1928A, but wanted a less expensive submachine gun.

The M1A1 was a stripped down Tommy gun, bringing the manufacturing cost down from $200 to about $45 but the U.S. military wanted it even cheaper. Inland Manufacturing designer George Hyde submitted a design with a wooden stock, pistol grip and stick magazine. It was tested in April 1942 and was adopted as the M2 the same month but barely entered production.

This World War 2 U.S. Auto-Ordnance M1A1 was the Thompson Submachine gun made after the U.S. military sought a less expensive SMG option than the costly M1928A before turning to the M3 Grease Gun. Rock Island Auction sold this M1A1 in December 2024 for $35,250.

Since Inland was producing the M1 Carbine, it subcontracted Hyde’s submachine gun design to Marlin for manufacture. The first manufacturing run produced unreliable and poorly built guns because some of the parts used a new production method. Marlin also faced supply problems and couldn’t get manufacturing going sufficiently. The government cancelled the M2, ordered more Tommy Guns and continued its search for an inexpensive and easy to produce submachine gun.

Unimpressed with the guns submitted for testing, the Army went directly to Inland and Hyde. Its design had a pistol grip, collapsible wire stock, a pivoting frame-mounted operating handle and 30-round stick magazine. Its tolerances ensured it would run reliably despite dirt and grit. An ejection port cover added to the reliability. Instead of select fire, the gun would be fully automatic to save money. That made its manufacturing cost slightly over $20 with the only machined parts being the bolt and barrel. The M3 Grease Gun was adopted.

The M3 Grease Gun was a wartime substitute for the Thompson Submachine Gun. This example has a flash hider on the muzzle. Rock Island Auction Company sold this gun in 2017 for $21,850.

M3 Grease Gun Designer George Hyde

Originally from Germany, Hyde immigrated to the United States where he anglicized his name. He was a machinist for Griffin & Howe and other gun designers before he became the chief gun designer for Inland Division of General Motors during World War 2 and designed the M3 Grease Gun. His first machine gun prototype that would be adopted as the M2 went head-to-head with the Thompson and others and came out on top. It was lighter and far more reliable than the Tommy Gun.

Once his design for the M3 Grease Gun was approved in December 1942 it went into production in early 1943. Inland manufactured the M1 Carbine, so production of the M3 Grease Gun went to Guide Lamp that had already manufactured 1 million of the single-shot FP-45 Liberator pistol.

The U.S. military in World War 2 developed the M3 Grease Gun to be a low-cost, easy-to-manufacture substitute for the Thompson Submachine Gun. Rock Island Auction Company sold this example in May 2024 for $49,938.

Historian Thomas B. Nelson wrote of the importance of the M3 Grease Gun from an ordnance and production perspective: “The simple design of the M3 submachine gun lends itself readily to mass production, and to ease of assembly and disassembly. In functioning, the weapon is superior to most other existing types. At the time the M3 was introduced, it represented an entirely new concept of weapon design in the American small arms ordnance system.”

Because production on the M3 started late, the government’s goal of retiring the Thompson didn’t occur until after the end of the war.

M3 Grease Gun and Other SMGs

During testing of a stamped metal submachine gun, the U.S. Army also looked at other countries’ guns, including the German MP 35 and MP 40, the Finish Suomi, British Sten Mk III among others. When it came time for manufacturing, Inland managers studied the Sten’s production line to see if any shortcuts could be identified for making the M3 Grease Gun.

Comparisons can be made to the M3 and other stamped metal SMGs like the Sten and the Soviet PPSh-41, but the American gun’s rate of fire wasn’t comparable. The M3 Grease Gun rate of fire was a tortoise-like 450 rounds per minute. The Sten and the MP 40 fired a bit faster at 500-600 rounds per minute. The Papasha, the Soviet’s PPSh-41, spat bullets at a blistering 1,000 rounds per minute.

The M3 Grease Gun had a fire rate of 450 rounds per minute, while the Soviet PPSh 41, like this one sold by Rock Island Auction Company in 2023, had a cyclical rate of 1,000 rounds per minute.

M3 Grease Gun Goes to War

Initially intended for tank crews and paratroopers, early reviews of the M3 Grease Gun weren’t glowing, after all soldiers were used to the machined M1 Garand, M1 Carbine and Thompson. The stamped metal gun appeared cheap, but troops soon appreciated its light weight, compactness and most importantly, its reliability.

The Ordnance Department continued to strive toward an easier to operate and maintain gun so modifications were made starting in 1944, especially to eliminate the operating handle, make the magazine catch stronger and beef up the rear sight. The ejection port was enlarged and even the metal stock was changed to serve as a cleaning tool. In December 1944 it was designated the M3A1.

A magazine diagram that shows how the M3 Grease Gun fires its moderate 450 rounds per minute.

The M3 Grease Gun received its baptism by fire on the biggest stage of the war, carried by U.S. Army Rangers and members of the 82nd and 101st Airborne divisions on D-Day. After landing, some soldiers returned to using the M1 Garand since it had greater range than the SMG. The Army would continue to widely use the M3 in the Korean War, and it would even serve in Vietnam.

The subsonic .45 ACP round and the M3 Grease Gun’s compact size made it a candidate to be suppressed, especially after seeing the British Sten with a suppressor. The Office of Strategic Services wanted a suppressed submachine gun for use behind enemy lines and contracted with High Standard Company to make 1,000 suppressed M3 Grease Guns. Guide Lamp drilled ports in the gun barrels and Bell Laboratories equipped the 14.5-inch-long suppressors. The gun was 80 percent as effective as the STEN which was more popular with OSS agents. The suppressed M3 Grease Gun was used by special forces in Vietnam.

This Guide Lamp M3A1 Grease Gun includes a silenced barrel like those made for the OSS in World War 2. Rock Island Auction sold it in December 2024.

M3 Grease Gun Goes to the Movies

The M3 and M3A1 received plenty of screen time thanks to the popularity of World War 2 films in the 1950s and 1960s. One of the last silver screen soldiers to carry the Grease Gun was Vince Vaughn who had a M3A1 in 2016’s “Hacksaw Ridge.”

The gun was truly a star in the 1967 film “The Dirty Dozen,” where the M3 Grease Gun was handled by nearly all of the Dozen, including Lee Marvin, Telly Savalas, Donald Sutherland, Jim Brown and Charles Bronson.  In the film, some of the men had M3s with magazines “jungle taped,” where the magazines are taped side by side. With one magazine loaded, the other is taped pointing down so they can be reversed for quick reloading.

M3 Grease Gun for Sale

The M3 Grease Gun showed that reliability and accuracy didn’t require a high price tag. Meant as a more cost effective and easier to produce submachine gun than the Thompson, the M3 and M3A1 proved to be an effective weapon in the hands of American GIs in World War 2, the Korean War and even the  Vietnam War. These and other World War 2 submachine guns like the PPSh-41 and Sten often can be found in Rock Island Auction Company Premier auctions.

A Soldier in Vietnam fires a M3A1 Grease Gun. Notice the flash hider on the muzzle.

Sources:

“The M3 Grease Gun,” by Leroy Thompson

“The M3 “Grease Gun” was designed to save money and kill Nazis,” by Paul Huard, We are the Mighty

“The M3 & M3A1 'Grease Guns'|” by Bruce N. Canfield, American Rifleman

Internet Movie Firearms Database