37 Mm Gun M3 - Variants

Variants

• Test variants:
  • T3 - the first prototype.
  • T7 - a prototype with semi-automatic horizontal sliding block breech.
  • T8 - a prototype with Nordenfelt eccentric screw breech.
  • T10 - standardized as M3 (1938) - an adopted version, with manual vertical block breech.
• Model variants
  • M3 towed version, manual breech.
    • M3A1 (1942) - version with threaded barrel end to accept a muzzle brake, which was never issued.
  • M5 (1939) - tank mounted variant with shorter barrel.
  • M6 (1940) - tank mounted variant with barrel of the original length and with semi-automatic breech.
• Carriage variants:
  • T1, T1E1 - prototypes.
  • T5, standardized as M4 - first adopted version.
  • M4A1 (1942) - carriage with improved traverse controls.
  • In 1942, the Airborne Command requested a version with removable trails. A prototype was tested, but in 1943 the project was dropped as unnecessary.

At least in one case, Fifth Army Ordnance in Italy fitted the gun experimentally with fifteen 4.5 in (110 mm) aircraft rockets, in five clusters of three, mounted above the shield.

Variants of the M3 should not be confused with other 37 mm guns in the U.S. service. Those other pieces included M1916 infantry gun of French design (these were later used extensively as subcaliber devices for heavy artillery.), M1 antiaircraft autocannon, M4/M9/M10 aircraft-mounted autocannons, M12/M13/M14/M15 subcaliber guns.