Aircraft / Aviation Vehicles & Artillery Small Arms Warships & Submarines Military Ranks Military Pay Chart (2024) Special Forces
Infantry Small Arms / The Warfighter

M3 (Grease Gun)

Submachine Gun (SMG) [ 1943 ]

The M3 Grease Gun was simple to operate and cheap to produce - important factors for a wartime weapon.

Authored By: Dan Alex | Last Edited: 08/18/2018 | Content ©www.MilitaryFactory.com | The following text is exclusive to this site.

The M3 "Grease Gun" was an economical submachine gun weapon designed during World War 2 (1939-1945) intended to arm the large quantity of incoming American troops with an equally-large quantity of small arms. The M3 appeared in number during 1943 in time to succeed the excellent-but-expensive (and complicated) M1 Thompson ("Tommy Gun") series of submachine guns. Design work on the new submachine gun began in 1942 and production ran from 1943 until 1945 to which some 700,000 examples were ultimately manufactured.

The nickname of "Grease Gun" was eventually given to the weapon American soldiers who likened its general appearance to that of a mechanic's grease gun.

Indeed the general appearance of the weapon was tubular and cast as large components to minimize parts needed. The pistol grip sat at the rear of the receiver in the usual way and a wire stock could be slid out from the sides of the receiver to provide a make-shift shoulder support. The trigger unit (solid trigger assembly) sat under the receiver and ahead of the pistol grip in the usual way. Very little in the way of ergonomics was afforded the shooter - the M3 was a utilitarian weapon to be sure. The magazine well sat ahead the receiver and accepted straight, detachable box magazines and also served as the forward grip (as in the German MP38/40 submachine gun series). The barrel was a simple cylindrical assembly set ahead of the receiver. Sighting devices were fitted over the weapon for some semblance of accurized fire but the submachine gun was always a short-to-medium-ranged weapon at its core.

A variant of the M3 series became the "M3A1" and this was a further evolution of the design . It followed the original into service during December of 1944 and was essentially developed to further simplify the production process and practices in order to streamline the end-product and ship the weapon out in the quantities required in wartime. Additionally, this period of revision allowed for a second look into correcting some inherent deficiencies in the original. As such the M3A1 was given a redesigned bolt-retracting mechanism which forced the prominent hinged cover to be enlarged some, allowing the user to fit his finger into the recess and pull the bolt back as needed. In another effort to make the weapon more versatile and - in effect more "battlefield friendly" - a reservoir of oil for in-the-field lubrication of parts was also incorporated into the pistol grip and various parts of the operating system were re-engineered to double as tools when the weapon was stripped down to its bare components.

By all accounts, the M3A1 was not that much of an improvement over the original M3 to which neither system ever achieved any level of acceptability or likeness with soldiers - they instead preferred their trusty M1 Carbines and M1 Thompsons for their sheer reliability and man-stopping power. Nevertheless, the M3 series went on to see extensive combat service through to the end of World War 2 and the series was in widespread circulation by the time of the Korean War (1950-1953).

Beyond that, production also occurred outside of the United States by foreign forces eager to take on a cheap, proven weapon that was nonetheless robust and fairly easy to operate.

The M3 model was produced by the Guide Lamp Division of General Motors in Detroit, Michigan, as well as the Ithaca Gun Company of Ithaca, New York. Some M3 models incorporated unusual-looking additions like muzzle-mounted flash hiders. Argentina designated their M3s as "PAM1" and "PAM2". The PAM1 was notable for its chambering of the 9x19 Parabellum German pistol cartridge while the PAM2 featured a grip-mounted safety. A suppressed model (detailed elsewhere on this site) was also noted which added an oversized assembly over the barrel to help reduce the telltale "crack" of the outgoing bullet for clandestine operations.©MilitaryFactory.com
Note: The above text is EXCLUSIVE to the site www.MilitaryFactory.com. It is the product of many hours of research and work made possible with the help of contributors, veterans, insiders, and topic specialists. If you happen upon this text anywhere else on the internet or in print, please let us know at MilitaryFactory AT gmail DOT com so that we may take appropriate action against the offender / offending site and continue to protect this original work.


Basics [+]
Guide Lamp Division of General Motors / Ithaca Gun Company - USA
Argentina; Bolivia; China; Ecuador; Guatemala; Japan; Macedonia; North Korea; Philippines; South Korea; United States National flag of Argentina National flag of Bolivia National flag of China National flag of Ecuador National flag of modern Japan National flag of Macedonia National flag of North Korea National flag of the Philippines National flag of South Korea National flag of the United States
Service Year
National Origin
United States

Overall Length
756 mm / 29.76 in
Barrel Length
203 mm / 7.99 in
Weight (Empty)
8.18 lb / 3.71 kg
Open Bolt; Blowback
Gas pressure from the rearward movement of the ignited cartridge case provides the needed bolt movement, ejecting the spent case and stripping a fresh case from the magazine.
System utilizes internal mechanism where bolt and associated working components are set to the rear of the receiver with no cartridge chambered; trigger actuation moves bolt forward, chambers cartridge, and fires bullet in single action - ultimately resetting during the complete cycle by way of the generated energy.
.45 ACP; 9x19mm Parabellum
*May not represent an exhuastive list; Calibers may be model-specific dependent; Always consult official manufacturer sources.
30-Round Detachable Box Magazine
Iron Front and Rear

Material presented above is for historical and entertainment value and should not be construed as usable for hardware restoration, maintenance, or general operation - always consult official manufacturer sources for such information.

Max.Effective Range
300 ft / 91.4 m | 100.0 yds
450 rpm
Muzzle Velocity
920 ft/sec / 280 m/sec

M3 - Base Production Series Designation
M3A1 - Modernized Variant Appearing in late 1944
PAM1 - Argentine Variant; chambered for the 9x19 Parabellum cartridge.
PAM2 - Argentine Variant; fitted with grip-mounted safety.

Military lapel ribbon for the American Civil War
Military lapel ribbon for pioneering aircraft
Military lapel ribbon for the Cold War
Military lapel ribbon for the Korean War
Military lapel ribbon representing modern aircraft
Military lapel ribbon representing special forces
Military lapel ribbon for the Ukranian-Russian War
Military lapel ribbon for the Vietnam War
Military lapel ribbon for the World War 1
Military lapel ribbon for the World War 2


1 / 6
Image of the M3 (Grease Gun)
Image copyright www.MilitaryFactory.com; No Reproduction Permitted.
2 / 6
Image of the M3 (Grease Gun)
Image copyright www.MilitaryFactory.com; No Reproduction Permitted.
3 / 6
Image of the M3 (Grease Gun)
Image copyright www.MilitaryFactory.com; No Reproduction Permitted.
4 / 6
Image of the M3 (Grease Gun)
Image copyright www.MilitaryFactory.com; No Reproduction Permitted.
5 / 6
Image of the M3 (Grease Gun)
Image copyright www.MilitaryFactory.com; No Reproduction Permitted.
6 / 6
Image of the M3 (Grease Gun)
Right side view of the M3 Grease Gun submachine gun; color

Disclaimer | Privacy Policy | Cookies

2024 Military Pay Chart Military Ranks DoD Dictionary Conversion Calculators Military Alphabet Code Military Map Symbols

The "Military Factory" name and MilitaryFactory.com logo are registered ® U.S. trademarks protected by all applicable domestic and international intellectual property laws. All written content, illustrations, and photography are unique to this website (unless where indicated) and not for reuse/reproduction in any form. Material presented throughout this website is for historical and entertainment value only and should not to be construed as usable for hardware restoration, maintenance, or general operation. We do not sell any of the items showcased on this site. Please direct all other inquiries to militaryfactory AT gmail.com. No A.I. was used in the generation of this content; site is 100% curated by humans.

Part of a network of sites that includes GlobalFirepower, a data-driven property used in ranking the top military powers of the world, WDMMA.org (World Directory of Modern Military Aircraft), WDMMW.org (World Directory of Modern Military Warships), SR71blackbird.org, detailing the history of the world's most iconic spyplane, and MilitaryRibbons.info, cataloguing military medals and ribbons. Special Interest: RailRoad Junction, the locomotive encyclopedia.

©2023 www.MilitaryFactory.com • All Rights Reserved • Content ©2003-2023 (20yrs)