Description
WWII U.S. Army D40720 Carriage Body for M49 Ring Mount
Item Overview
This WWII U.S. Army D40720 carriage body formed the main structure of the roller carriage used with several circular truck machine-gun mounts. Collectors often call the completed carriage a trolley or skate because it traveled around the gun ring. The carriage supported a separate cradle for either the Browning M2 heavy-barrel .50-caliber machine gun or the Browning M1919A4 .30-caliber machine gun. This listing is for the carriage body only, not a complete carriage, gun mount, or weapon.
Identification and Features
The original Ordnance drawing number is D40720, and the related wartime item code is A55-01-24080. The body was later cataloged as part number 6540720 under NSN 1005-00-654-0720 with the federal nomenclature “Body, Carriage.” The identified manufacturer or supplier is Trackson Company of Milwaukee, Wisconsin. D40720 is the main body rather than the complete D40721 carriage assembly.
- Original nomenclature: Body, carriage
- Drawing number: D40720
- Ordnance item code: A55-01-24080
- Later part number: 6540720
- Later NSN: 1005-00-654-0720
- Manufacturer or supplier: Trackson Company, Milwaukee, Wisconsin
- Parent assembly: Carriage Assembly D40721
- Associated ring mount: M49
- Related truck mounts: M32, M36, M37, M37A1, and M37A2
- Supported weapons: Browning M2HB .50 caliber and Browning M1919A4 .30 caliber
- Offered configuration: Inert carriage body only
How It Worked
The D40720 body held the rollers, brake parts, pintle sleeve, and related hardware used by the completed carriage. When assembled, the carriage rolled around a circular track mounted above the truck cab or body. This allowed the gunner to move the weapon around the ring for wide horizontal coverage. The weapon cradle rotated in the carriage’s pintle sleeve and provided separate elevation adjustment. A brake lever locked the carriage to the track when the gunner selected a firing position. The rollers, brake-detent springs, plungers, handles, fasteners, and other parts required to form Carriage Assembly D40721 are separate components.
Weapon and Mount Applications
This carriage-body design is associated with the M49 circular ring mount and the related M32, M36, M37, M37A1, and M37A2 truck machine-gun mounts. The M32, M36, M37, and M37A2 designations identify mount models, not vehicle models. Army instructions state that these truck mounts could carry either the flexible Browning M2 heavy-barrel .50-caliber machine gun or the Browning M1919A4 .30-caliber machine gun.
Historical Background
During World War II, the U.S. Army equipped many cargo trucks, tractors, prime movers, and support vehicles with machine-gun mounts for defense against aircraft and ground threats. A circular track gave the gunner a broad field of fire without requiring several fixed mounting points. Different truck bodies and cab styles required different support posts and braces, which led to the M32, M36, M37, M37A1, and M37A2 mount variations. Army manuals noted that the parts above and including the circular rails were generally identical among these related mounts, while the lower mounting supports changed to fit different vehicles.
History of Use
Army records document these roller-carriage mounts on several types of wartime trucks. M36 applications included GMC 2½-ton trucks, GMC amphibious trucks, Studebaker cargo trucks, Diamond T heavy trucks, Federal and Autocar tractors, and White, Corbitt, and Mack prime movers. Closed-cab and wooden-body trucks used other mount versions suited to their construction. In service, the ring-mounted M2HB provided powerful defensive fire against low-flying aircraft, vehicles, equipment, and ground positions. The lighter M1919A4 offered another option when a .30-caliber weapon was preferred. These mounts served in training, convoy protection, local defense, and combat operations.
Condition
This is an inert military-surplus carriage body. It may show original or later paint, scratches, dents, oxidation, grease, dirt, worn markings, machining marks, and storage wear. The part has not been represented as a complete or installation-ready carriage assembly. This listing includes one D40720 carriage body only; rollers, bearings, brake hardware, springs, plungers, handles, cradle, pintle, gun ring, supports, fasteners, weapons, and other parts are not included unless specifically stated. Please check the pictures for the general condition of the item.
Ideal For
This original carriage body is a useful display or restoration component for collectors studying U.S. Army truck armament, Browning machine guns, and World War II vehicle equipment. Its documented drawing and federal numbers also make it suitable for reference collections and parts identification.
- M49 ring-mount restoration projects
- M32, M36, or M37-series truck-mount displays
- World War II military-truck collections
- Browning M2HB and M1919A4 exhibits
- U.S. Army Ordnance collections
- Military museums and educational displays
Approx length 10", Approx width 8", Approx height 8", Approx weight 18lbs.
Pictures are stock images of our inventory. Unless otherwise noted, you will not be receiving the exact item shown in the pictures. The pictures are representative of the item’s general condition. The item you receive might be slightly better, or worse, condition than was shown in the pictures.
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