Original Item: Only One Available. This is a lovely, inert example of a 37mm round as used with the Browning M4 Autocannon. The round is totally inert and is unable to be rendered live again. The round is in compliance per the current BATF standards governing ordnance.

Not Available For Export.

This shell used the M56 point detonating fuze. The complete round weighs 1.99 lb (900 g); as fired, the projectile weighs 1.34 lb (610 g). The 0.16 lb (73 g) charge of M2 powder is a Hercules NG formula of single perforated grains with 0.03 in (0.76 mm) web and gives the projectile the prescribed muzzle velocity of 2,000 ft/s (610 m/s).

The M54 used a shell-destroying tracer in addition to the point-detonating fuze. The tracer had a burning time of three seconds at the end of which it set off an igniting relay charge of 1.68 gr (0.109 g) of Grade A-5 Army Black Powder which ignited a relay pellet that detonated the charge, destroying the shell before ground impact.

The bursting charge of tetryl weighed 0.10 lb (45 g), and the alternate Composition "A" charge weighs 0.105 lb (48 g). The tetryl loading consisted of a 200 gr (13 g) tetryl pellet pressed into the shell cavity under 9,000-10,000 psi (60-70 MPa) pressure and the remainder of the charge of two equal increments pressed under approximately 9,000 psi (62 MPa) pressure. The Composition "A" bursting charge is loaded in the same manner as the tetryl charge, except that the relay pellet with the Composition "A" weighs 36 gr (2.3 g) as against 23 gr (1.5 g) for the pellet used with the tetryl load.

The round measures 13” tall and the cardboard storage tube measures approximately 14” tall. Both the tube and the round itself feature legible markings:

A lovely example ready for display!

The 37 mm Automatic Gun, M4, known as the T9 during development, was a 37 mm (1.46 in) recoil-operated autocannon designed by Browning Arms Company. The weapon, which was built by Colt, entered service in 1942. It was primarily mounted in the Bell P-39 Airacobra and P-63 Kingcobra, with the U.S. Navy also utilizing it on many PT boats.

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 non recoiling 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.