M4 cannon
| 37 mm Automatic Gun, M4 | |
|---|---|
 |
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| Type | |
| Place of origin | United States |
| Service history | |
| In service | 1942 |
| Used by |
United States Soviet Union |
| Wars | World War II |
| Production history | |
| Designer | John Browning |
| Designed | 1921-1938 |
| Manufacturer | Colt |
| Produced | 1939 |
| Specifications | |
| Weight | 213 lb (97 kg) |
| Length | 89.5 in (2.27 m) |
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| Shell | 37x145mmR M4 |
| Caliber | 37 mm (1.46 in) |
| Action | recoil operation |
| Recoil | 9⅝ in (245 mm) |
| Rate of fire | 150 rpm |
| Muzzle velocity | 2,000 ft/s (610 m/s) |
| Feed system | 30-round magazine |
The 37 mm Automatic Gun, M4, known as the T9 during development, was a 37 mm (1.46 in) recoil-operated designed by Browning Arms Company. The weapon, which was built by Colt, entered service in 1942. It was used in the Bell P-39 Airacobra and P-63 Kingcobra.
Designed primarily as an anti-aircraft weapon, the gun had a muzzle velocity of 2,000 ft/s (610 m/s) and a cyclic rate of 150 rounds per minute. It was normally loaded with high-explosive shells, but could also be loaded with the M80 armor-piercing shell, which could penetrate 1 inch (25 mm) of armor plate at 500 yd (460 m). It was magazine-fed and could be fired manually or by remote control through a solenoid mounted on the rear of the gun.
Recoil and counter-recoil were controlled hydraulically by means of a piston and spring combination connected to the recoiling mechanism and operating in an oil-filled recuperator cylinder mounted to the stationary trunnion block assembly. The recoiling mechanism of the gun included the tube and tube extension, recuperator piston and piston rod, lock frame assembly, driving spring assemblies, and the breechblock assembly. The nonrecoiling parts included the trunnion block group, the feed box and feeding mechanism, the recuperator cylinder and bushing, the back plate group, and the manual charger assembly.
As the gun was originally designed, ammunition could be fed by a 5-round clip, a 15-round link belt, or a non-disintegrating 30-round endless belt magazine. The 30-round endless belt version was used exclusively in production. The M4 gun fed only from the left.
The 30-round endless belt magazine was given the designation M6; it had an oval-shaped framework (nicknamed a "horsecollar magazine" from its shape) providing a track for the endless belt.
Initial loading and cocking of the gun were accomplished manually. A safety feature incorporated in the design of the trigger mechanism prevented firing the round until the breech-block assembly was in the battery position.
The breech was locked and unlocked by recoil action which brings the operating level guide pins against cams to raise and lower the breechblock. The function of the breechblock was to assist in the final chambering of the round, close the breech, and actuate the trigger trip. It also provided a mounting for the firing pin.
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Wikipedia