M1 40mm Bofors

M1 40mm Bofors anti-aircraft gun

Description

Technical Data

Specifications

Details view

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Description

The M1 anti-aircraft gun is the single barrel 40mm Bofors which was in service in the United States Army during the Second Wolrd War. The dual version of the gun was mounted on an M24 Chaffee tank chassis and was called the M19 Gun Motor Carriage. This gun is recoil operated and is intended primarily for antiaircraft fire but it may also be used against ground targets. It fires fixed ammunition in rapid bursts of automatic fire at the rate of 120 rounds per minute. It can also operate on single fire. The gun is equipped with a percussion type firing mechanism. The M1 40mm are still in service with some armed forces in Middle East and Africa.

Variants

- M2: improved version of M1
- M2A1: new carriage with higher gear ratios in the traversing mechanism. This change allowed the M2A1 mount to traverse the Bofors three times farther in azimuth in a single turn of the lateral pointer's handcrank when compared to the M2. The higher ratio of the M2A1 helped the gun to track fast-flying aircraft, even if enemy pilots dropped low and flew close-in.

Technical Data

Armament

The main armament of the M1 Bofors includes a 40 mm cannon caliber. The ammunition was packed in clips of four rounds that fed via a chute on the top of the gun. The rapid-firing gun could operate up to 120 rounds per minute in bursts, faster than they could be fed by the crew. The M1 40mm anti-aircraft gun used a standard high-explosive shell with a sensitive point-detonating fuse designed to burst upon impact with the relatively lighter materials used in aircraft construction. If the shell did not make contact with a target, the fuse destroyed the projectile at the tracer burnout range of approximately 3,500 yards. Armor-piercing shot was also available to take on ground targets. Each 40mm round weighed about two pounds.

Design

The M1 40mm anti-aircraft gun was mounted on a four-wheel trailer which can be towed by a light truck. The platform allowed the gun a 360° traverse and outriggers were provided to stabilize the turntable platform for firing. No shield for the crew was provided. The carriage is equipped with electric 4-wheel brakes operated from the prime mover and manually operated mechanical rear wheel brakes. The crew of each weapon had an azimuth and elevation tracker seated in bucket seats on each side of the weapon. The elevation tracker had a foot pedal to fire the gun when the sight picture was right.

Operations

The M1 40mm anti-aircraft gun was operated either by sight control or by director control. The carriage is equipped with manual and power operated elevating and traversing mechanisms. Manual elevation is between -6° and +90°. Power elevation is normally between zero and +88°. Traverse is 360 degrees. The carriage is provided with a mechanical firing linkage operated by means of foot pedals.

Accessories

Each gun platoon (four guns) had an M5 Director, connected by cables to the guns and all fed by a common generator. Later, M-5 Director was replaced by the M-7 Computing Sight ("Weissight"), an "on-carriage" aiming device mounted on the gun with tracking telescopes for the azimuth and elevation trackers. The M7 Computing Sight eliminated the need for a separate director section, its director, generator, cables, and centralized control.

Specifications