M3 Grease Gun submachine gun

The M3, commonly known as the "Grease Gun" (sometimes incorrectly translated as "oil can"), is an American submachine gun from the World War II era, designed to replace the complex and expensive Thompson submachine gun. The weapon was developed by designer George Hyde between 1942 and 1943 and was manufactured by General Motors in its Guide Lamp division.

The M3 was equipped with a 30-round magazine chambered for .45 ACP ammunition. Due to its simple construction, which primarily consisted of stamped metal parts, the M3 was cheaper and quicker to produce than the Thompson, making it an ideal weapon for mass production during the war. The Grease Gun quickly earned its nickname due to its distinctive shape and operation, which resembled tools used for lubricating machinery. Despite its apparent simplicity, the M3 was highly effective in close-quarters combat, making it a popular choice among American soldiers in both Europe and the Pacific.

After World War II, the M3 remained in the arsenal of the U.S. armed forces and was deployed during both the Korean and Vietnam Wars. Its reliability and compact design continued to make it useful in combat situations where speed and maneuverability were essential. The weapon remained in service in various countries' armed forces until the 1990s.

The Gulf War was one of the last military operations where the M3 was deployed. It was primarily used by soldiers in support roles, vehicle crews, and some special forces units, who valued its compact size and ability to fire the powerful .45 ACP rounds.

In addition to the standard M3 version, there was also an improved version known as the M3A1, introduced in 1944. The M3A1 eliminated the original cocking lever, replacing it with a simpler mechanism where the bolt was cocked directly with the finger. This change improved the weapon's reliability and simplified its maintenance. The M3A1 became the preferred variant in the later stages of World War II and in post-war conflicts.