M3 and M3A1 Grease Gun

[David]

The US military saw the definite need for submachine guns on the battlefield (as displayed by the usefulness of the British Sten and the German MP38/40 submachine guns). Though the US was still technically neutral at this point, steps were taken with a team led by weapons designer George Hyde to produce a weapon based on the British Sten submachine gun - simple to produce yet rugged and effective to use - this became the order of the day. The Japanese attack on Pearl Harbor changed priorities for American design and production and more time and energy was placed into putting the M3 in frontline service as fast as humanly possible.
The M3 'Grease Gun' came into service in December of 1944. The name Grease Gun came from the appearance of the weapon and it's similarities to a mechanic's grease can. It was just as ugly as the British Sten counterpart on which the design was based on.
The M3 Grease Gun saw first combat in Europe, and not to much fanfare. The shortcomings of such a simply-produced weapon system became apparent. Working parts broke off, the retractable wire butt was prone to bending and the cocking handles broke off in the heat of battle. Troops on the European Front were more in favor of using the M1 Thompson or even captured MP38s or MP40s whenever they could. Even the .30 caliber M1 Carbine was a better fit for most troops than was the M3 Grease Gun.
Never the less, the M3 was pressed into service through assembly lines built for motor cars and trucks (mass production - hence the shortcomings of the weapon). American soldiers in the Pacific saw more of the M3 than the European Theater American soldiers did, effectively 'forcing' its use onto frontline troops and supplementary troops such as truck drivers and maintenance crews due to their compact size and effectiveness in close quarters.
The M3 system was designed with mass-production in mind. The M3 featured all metal with simple steel stampings. It was also designed to be easily converted to fire 9mm rounds by changing the barrel, magazine and breech lock. The weapon had no safety to speak of and could only be fired in full automatic mode.
Changes in 1944 offered up an even more simpler production method for the M3 which came known to be the M3A1 and was then accepted into full service. An enlarged ejection cover was fitted along with a flash hider. An oil reservoir was fitted into the handle. The frequency of jamming was also reduced by adding a plastic dust cap to magazines. It was then decided to begin phasing out production of the Thompson in favor of the M3 at this point.
American soldiers never fully accepted the M3. The system was prone to breaking and was fitted with an imperfect ammunition feed. The absence of a safety and the ability to fire only in full-automatic worked against it, as did the meer looks of the machine. But in a war that demanded production over quality to win, the M3 Grease Gun grudgingly won over its critics and beat out the much popular and well-liked M1 Thompson.
Nearly 700,000 M3 Grease Guns were produced in the United States, plus many more produced through license in other countries.
Specifications for the M3 Grease Submachine Gun:

Designation: M3
Might Be Known As: Grease Gun
Classification: Submachine Gun
Caliber: .45 ACP Caliber
Length: 29.75 inches
Weight: 8lb 3oz (unloaded)
Magazine Capacity: 30-round detachable box
Rate of Fire: 400 rounds per minute
Muzzle Velocity: 910 feet per second
Variants: M3 (prototype model); M3A1 (full production model)
More Pictures of the M3 Grease Gun:

Shown with wire butt stock retracted. The M3 served well as a 'crew-served weapon' for tank troops and truck drivers due to it's compact size.