page_title: M45 Quadmount
section_title: Mountings
hierarchical_section_title: M45 Quadmount / Mountings
caption_attribution_description: English: M20 trailer mount
context_page_description: The M45 Quadmount was a weapon mounting consisting of four of the "HB", or "heavy barrel" .50 caliber M2 Browning machine guns mounted in pairs on each side of an open, electrically powered turret. It was developed by the W. L. Maxson Corporation to replace the earlier M33 twin mount. Although designed as an anti-aircraft weapon, it was also used against ground targets. Introduced in 1943 during World War II, it remained in US service as late as the Vietnam War.
context_section_description: During World War II, the M45 turret was mounted on two specific systems; the M16 Multiple Gun Motor Carriage and the M51 Multiple Machine Gun Carriage.  When mounted on the M20 trailer, it was known as the M55 Machine Gun Trailer Mount, but this system had not finished testing before the cessation of hostilities.  M51s were withdrawn from service by the end of World War II in favor of the M55.
  During the Korean War, the M55 and M16 saw extensive combat, and lessons learned in Korea led to the conversion of an additional 1200 M3 halftracks into the M16A1 variant by adding an M45 turret.  These can be identified by the lack of fold-down armor and rear troop door on the crew compartment and were often fitted with the roller front bumper instead of the winch bumper fitted to all M16s.  In 1954 an additional modification was made to roughly 700 M16 MGMCs, adding the rear troop door and bolting the fold-down armor in the up position.  This modification became known as the M16A2 MGMC.
  The M55 received a new, more powerful generator in the 1960s and served through the Vietnam War, usually mounted in the back of an M35 2.5 ton or M54 5-ton truck.
caption: M20 trailer mount, 1947
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