Description
Technical Manual Overview
This original U.S. Army Technical Manual TM 9-2010 covers the M45 series of multiple .50-caliber machine gun mounts, the M55 machine gun trailer mount, and the M20 trailer. Published on December 4, 1953, it provides operating and organizational maintenance information for these important antiaircraft and ground-support weapons. The manual is a useful period reference for collectors, military vehicle restorers, researchers, and museums studying American multiple-gun systems from World War II through the early Cold War.
Publication Details
TM 9-2010 was issued by the Department of the Army as the primary operator and organizational maintenance reference for the covered mounts and trailer equipment.
- Manual Number: TM 9-2010
- Former Manual Number: TM 9-223
- Publication Date: December 4, 1953
- Publisher: Department of the Army
- Equipment: M45, M45C, M45D, and M45F multiple .50-caliber machine gun mounts
- Trailer Mount: M55 multiple .50-caliber machine gun trailer mount
- Trailer: M20 mount trailer
- Manual Level: Operation and organizational maintenance
- Period: Korean War and early Cold War
Manual Contents
This manual explains equipment identification, operating controls, normal operation, unusual operating conditions, preventive maintenance, lubrication, troubleshooting, and organizational repair. Detailed sections cover the electrical system, storage batteries, hydrometer, power charger, trunnion group, power drive, gunner’s seat, armor shields, firing mechanism, trailer wheels, electrical connections, frame, and related equipment. It also includes information on the associated .50-caliber machine guns, ammunition chests, M18 reflex sight, shipment, limited storage, and destruction procedures intended to prevent enemy use.
Publication History
TM 9-2010 replaced the earlier TM 9-223 dated July 27, 1944 and incorporated selected material for the M20 trailer that had appeared in TM 9-789. It expanded the Army’s published coverage to include later M45-series variants and related sighting equipment. Change 1 followed in May 1965, and the Army was still issuing updates to the manual in 1985, showing how long this equipment remained in military inventories and support channels.
Documented Equipment Applications
The publication applies directly to the M45, M45C, M45D, and M45F multiple machine gun mounts. The M45C mount installed on the one-ton, two-wheel M20 trailer formed the complete M55 machine gun trailer mount. M45-series turrets were also used with M16-series multiple gun motor carriages, allowing the four-gun weapon assembly to serve in both self-propelled and towed roles.
M45-Series Mount History
The M45 was developed by the W. L. Maxson Corporation as an improved four-gun mount using Browning M2HB .50-caliber machine guns. Introduced during World War II, it placed two guns on each side of an armored gunner’s compartment. Electric controls provided rapid powered traverse and elevation, while rechargeable batteries supplied power to the drive system. Although designed mainly for antiaircraft defense, its concentrated fire also proved highly effective against troops, vehicles, defensive positions, and other ground targets.
M55 Trailer Mount History
The M55 combined an M45C multiple machine gun mount with the M20 trailer to create a towable weapon system. This arrangement allowed crews to move the quad .50-caliber mount behind a suitable vehicle, place it at a defensive position, and operate it without requiring a dedicated half-track chassis. The trailer-mounted design was useful for airfield protection, perimeter defense, road security, and other missions where a powerful but movable automatic-weapons position was needed.
M20 Trailer History
The M20 was a two-wheel, one-ton trailer designed to carry and support the multiple machine gun mount. Its frame, wheels, stabilizing equipment, electrical connections, and mounting hardware formed the mobile base of the M55 system. The trailer made it possible to reposition the weapon while preserving the wide traverse and high-angle fire needed for antiaircraft work.
.50-Caliber Weapon-System Background
The M45 family used four Browning M2HB heavy machine guns firing standard .50-caliber ammunition. The M2HB had the range, striking power, and reliability needed for defense against low-flying aircraft and lightly protected ground targets. Mounting four guns together produced a dense volume of fire, while the powered turret allowed the gunner to follow fast targets more easily than with a single manually aimed weapon.
History of Use
M45 mounts entered service during World War II on self-propelled and trailer-mounted platforms. Crews soon found them valuable for ground support as well as air defense. M16 multiple gun motor carriages and M55 trailer mounts saw extensive combat during the Korean War. Related quad .50 mounts remained useful during the Vietnam War, where they protected bases and were fitted to cargo trucks for convoy escort and defense against ambushes.
Ideal For
This period Army publication offers valuable technical and historical information for several collecting and research interests.
- U.S. military technical manual collectors
- M45 quad .50 mount owners and restorers
- M16 multiple gun motor carriage researchers
- M55 and M20 trailer restoration projects
- Browning M2HB machine gun historians
- World War II and Korean War collections
- Military museums and historical displays
- Cold War air-defense researchers
Approx length 6", Approx width 9", Approx height .35", Approx weight .7lbs.
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