Description
U.S. Army Technical Manual TM 9-1252 for 40mm M1 and M2 Automatic Guns, M2A1 Antiaircraft Gun Carriage, and M3 and M4 Gun Mounts, March 1951
Item Overview
This U.S. Army technical manual covers field and depot maintenance for the 40mm Automatic Gun M1, 40mm Dual Automatic Gun M2, 40mm Antiaircraft Gun Carriage M2A1, 40mm Gun Mount M3, and Twin 40mm Gun Mount M4. Published as TM 9-1252 on March 5, 1951, it provides detailed instructions for maintaining several important American Bofors-type weapon installations. This listing is for the technical manual only. It does not include a gun, carriage, mount, vehicle, ammunition, sight, tool, or other equipment.
Publication Details
This edition was prepared using information current through October 11, 1950. It replaced the April 24, 1942 editions of TM 9-1252 and TM 9-1253, Technical Bulletin 9-1253-FE1, and related sections of Technical Bulletin ORD 256.
- Manual number: TM 9-1252
- Publication date: March 5, 1951
- Manual type: Field and depot maintenance
- Primary caliber: 40mm
- Issuing authority: Department of the Army
- Country of origin: United States
- Historical period: Early Cold War and Korean War
- Item included: Technical manual only
Equipment Covered
The manual combines maintenance information for single-gun, dual-gun, towed, pedestal, and self-propelled 40mm installations. The M3 is a single-gun mount for the M1, while the M4 is a twin mount for the dual M2 gun assembly.
- 40mm Automatic Gun M1: Recoil-operated single automatic gun
- 40mm Dual Automatic Gun M2: Paired automatic-gun assembly
- 40mm Antiaircraft Gun Carriage M2A1: Four-wheel mobile carriage for the M1 gun
- 40mm Gun Mount M3: Pedestal or vehicle mount for one M1 gun
- Twin 40mm Gun Mount M4: Powered twin mount used on the M19A1 Gun Motor Carriage
Manual Coverage
TM 9-1252 contains instructions for inspection, disassembly, repair, rebuilding, assembly, adjustment, and final testing. Major subjects include barrels, automatic loaders, recoil cylinders, breech mechanisms, firing linkages, equilibrators, elevating and traversing mechanisms, platforms, shields, axles, brakes, electrical equipment, special tools, and overhaul standards. This work was beyond the routine maintenance normally performed by operating crews.
About the 40mm M1 and M2 Guns
The American 40mm M1 was based on the Swedish Bofors automatic cannon, one of the most successful antiaircraft weapons of World War II. The recoil-operated gun fired fixed ammunition from four-round clips and could operate in automatic or single-fire mode. Its rated automatic rate was about 120 rounds per minute. The dual M2 assembly paired two guns for a combined rate of about 240 rounds per minute. Both versions were intended mainly for antiaircraft fire but could also engage vehicles, troops, and other ground targets.
M2A1 Antiaircraft Gun Carriage
The M2A1 was a two-axle, four-wheel trailer carriage designed to carry one M1 gun. It had independent spring suspension, electric and mechanical brakes, stabilizing outriggers, manual and powered aiming controls, and a full 360-degree traverse. A prime mover towed the carriage between positions, while leveling jacks and outriggers formed a stable firing platform after deployment.
M3 and M4 Gun Mounts
The M3 was a manually aimed pedestal mount that could be bolted to a vessel, vehicle, or fixed foundation. It was first produced for naval service and was also issued to the Army Transportation Corps. The M4 carried the dual M2 gun assembly and included manual and powered elevation and traverse. It formed the main armament of the M19A1 Twin 40mm Gun Motor Carriage, which used a tracked M24 Chaffee-family chassis.
Weapon-System History
The original Bofors design was developed in Sweden during the 1930s and was adopted by many nations before and during World War II. American factories produced adapted versions in large numbers for the Army and Navy. The weapon filled the gap between heavy machine guns and larger antiaircraft artillery, giving crews an effective defense against low-flying aircraft. Single, twin, and quadruple installations protected ships, airfields, ports, troop positions, and mobile formations.
History of Use
The 40mm Bofors family saw extensive Allied service during World War II and remained important after 1945. Towed M1 guns protected military sites and field forces, while pedestal-mounted guns served aboard vessels and at fixed positions. The M19 and M19A1 self-propelled systems carried twin 40mm guns during the Korean War. Because enemy air activity was limited, crews often used these weapons against infantry, fortified positions, and other ground targets. The March 1951 publication date places this manual during that active Korean War service period.
Collector and Research Value
TM 9-1252 is a useful reference for studying the 40mm Bofors system, M19A1 Gun Motor Carriage, military antiaircraft development, and Army ordnance maintenance. Its wide coverage makes it valuable for restorers, museums, vehicle owners, military historians, and technical-manual collectors.
Condition
This vintage military technical manual may show cover wear, edge wear, folds, yellowing, stains, writing, stamps, punched holes, loose pages, or other signs of age and storage. Printing details and condition may vary between available copies. Please check the pictures for the general condition of the item.
Ideal For
This manual is well suited for collections, research projects, restorations, and exhibits related to American antiaircraft weapons and tracked fighting vehicles.
- U.S. Army technical-manual collections
- 40mm M1 and M2 automatic-gun research
- M2A1 carriage restoration references
- M3 and M4 gun-mount research
- M19 and M19A1 vehicle displays
- World War II and Korean War exhibits
- Museum and archival collections
Approx length 6", Approx width 9", Approx height .75", Approx weight 1.5lbs.
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