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Carriage, Motor 155-mm Gun, M40

Discussion in 'Allied Motorised Weapons' started by Jim, Jan 27, 2008.

  1. Jim

    Jim New Member

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    The first 155-mm (6.1-in) self-propelled gun produced in quantity by the Americans during World War II was the M12, a design originally known as the T6 and built on to a converted M3 medium tank chassis. Initially this weapon was not considered for service as it used obsolescent World War I ordnance that had become available once the type’s original carriages had become too worn for further use. However, once accepted for service, they gave good performance although it was agreed that a new ordnance was required if a long-term weapon was to be procured.
    Starting in December 1943 a new weapon/carriage combination was initiated. The gun was the 155-mm MIAI known as the ‘Long Tom’ (with 20 rounds) and the carnage was based on the chassis of the M4A3 medium tank, though much widened and fitted with the latest high volute suspension springing. The engine was moved from the rear to a new forward position, and to absorb some of the recoil forces a spade was added to the rear; this latter could be raised for travelling, A working platform under the breech was also provided. The gun had a range of 23514 m (25,715 yards) and fired a projectile weighing 43,1 kg (95 lb), which made it a very useful counter battery and long-range bombardment weapon. Maximum armour thickness was 12.7 mm (0.5 in) the development of this Carriage, Motor, 155-mm Gun, M40 took rather longer than expected, so it was not until January 1945 that the first production examples rolled off the lines. They were rushed across the Atlantic in time to see the end of the war in Germany.
    M40s took part in the bombardment of Köln and the short campaigning after this. Between January and May 1945 no less than 311 M40s were built, and production continued after the war, The M40 was to see its most concerted use during the Korean conflict, where it proved to be an excellent weapon/carriage combination.
    On the M40 there was no protection for the crew as the type was designed for use so far behind the front line that none would be necessary. The M40 had a crew of eight, and there was provision on the carnage for their weapons and kit. The same carriage was also used to mount a 203-mm (8-in) howitzer, but this version (the Carriage, Motor, 8-in Howitzer, M43), was not used in great numbers; only 48 were built.
    After 1945 M40s were distributed to many other armies, The British Army accepted a number and used them for some years. More were used by nations such as France, with whom the type saw extensive service in Indo-China.
    There was one variant of the M40, the T30 Cargo Carrier. As its designation implies, it could be used as a general supply carrier though its normal deployment was for the ammunition supply of M40 batteries. Not many were built as most of the manufacturing potential was concentrated on producing gun carriers.
    One of the main claims to importance of the M40 was that it paved the way for the current generation of self-propelled weapons. It was produced at a time when nuclear warfare was just making its debut, and the need for protection against this new battle hazard was particularly noticeable on the M40 with its open fighting platform.
    The type was therefore used extensively for trials and experiments designed to provide protection for the crew. The M40 proved beyond doubt that the only proper protection comes from an armoured turret, and most modern self-propelled weapons now use such an arrangement.

    Although the M40 arrived on the scene later in the war, it was one of the best of all wartime self-propelled equipments and went on to a long post-war career. It used the chassis of the M4 tank as a basis.

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    Specification: [​IMG]

    M40
    Type: self-propelled gun
    Crew: 8
    Weight: 37195 kg (82,000 lb)
    Engine: one Continental 9-cylmder radial piston engine developing 294.6 kW (395 hp)
    Dimensions:
    Length overall: 9.04 m (29 ft 8 in) and hull only 6.65 m (21 ft 10 in)
    Width: 3.15 m (10 ft 4 in); height 2.84 m (9 ft 4 in)
    Performance:
    Maximum speed: 38.6 km/h (24 mph); range 161 km (100 miles)
    Armament: one 155-mm (6,1-in) gun
     

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