UNITED24 - Make a charitable donation in support of Ukraine!


M40 / M41 155mm Self-Propelled Howitzer

Adopted in February 1945 and used in the Korean War, the 155mm Gun Motor Carriage M40 mounted either a 155mm Gun M1A1 or M2 mounted to the rear deck of a modified M4 Sherman medium tank chassis. Crewed by eight men, it had a range of 25,722 yards firing a 95-pound projectile. The 155mm Howitzer Motor Carriage M41 was adopted in June of 1945, and a total of 85 were accepted by the army. It incorporated a 155mm Howitzer M1 with a maximum range of 16,360 yards on the rear of an open M24 Chaffee light tank chassis. The M41 saw service in both World War II and the Korean War.

This gun motor carriage was designed to provide highly mobile heavy artillery capable of being put into action in the minimum time. It can be used effectively against targets of the type likely to be encountered in the war with Japan. Principal armament is the 155 mm Gun MlAl or M2 on Mount M13 (T14), a mount consisting essentially of the top carriage, recoil mechanism, and the elevating and traversing mechanisms from the standard field piece. Mounted in the center rear of the vehicle, the gun can be elevated from -5 to +55 and can be traversed 18' left and 18" right.

A spade at the rear of the vehicle can be dropped to the ground and imbedded for the purpose of increasing the stability of the vehicle while firing. This vehicle is based on a chassis that uses components of the Medium Tank 3T4 but is wider, lower, longer and lighter in weight than the M4 chassis. The engine was moved from the rear to a new forward position. The power train components are standard items used in current production models of medium tanks of the M4 series, as are also the suspensions and tracks. The suspension is of the horizontal volute spring type, with three bogies on each side. The tracks are 23 inches wide and have center guides.

Power is supplied by a Continental R-975-C4 engine through a constant, mesh synchronized transmission that provides five speeds forward and one reverse. The vehicle has stowage for 20 rounds of 155 mm ammunition, including propelling charges, primers and fuzes, and for small arms ammunition and grenades. The differential and final drive housing used is the same as for M4 series tanks, varying from 4 inches to 2% inches in thickness. Side armor below the fender line is 1-inch and other armor is %-inch. It has, in addition, gun shields of %-inch armor plate. The 155 mm Gun Motor Carriage M40 (T83) had a maximum speed of 24 m.p.h. and a cruising range of approximately 150 miles.

The developent of the 155 mm Gun Motor Carriage M40 took rather longer than expected, so it was not until January 1945 that the first production examples rolled off the lines. Rushed across the Atlantic to hasten the end of the war with Germany, they participated in the bombardment of Cologne and the short campaiging thereafter. A total of 311 M40s were built between January and May 1945, and production continued after the end of the War. The M40 saw concerted use in Korea, where it proved a most excellent gun/carriage combination.

Strongly fortified positions, such as, concrete pillboxes, log and/or earth bunkers or caves fell easy prey to the fire power of these weapons. The vulnerable points of any of these targets are the many openings present-such as, gun ports, doors or the opening at the mouth of caves. Hits secured through openings detonate inside the strong point and effectively reduce it by killing the personnel and destroying the materiel present. For attack of this sort best results are obtained at close range by direct fire. The 155 mm Gun Motor Carriage, M40 (T83) is particularly suitable for just this type of mission. The mobile mount permits the piece to be brought up into position quickly while the armor protection affords a cover for the gun crew while the point is being reduced.

The M40 provided no protection for the crew, as it was intended for use far behind the lines, where it was thought none would be needed. The advent of nuclear weapons made it increasingly apparent that protection was needed, and subsequent self-propelled guns featured an enclosed turret for the crew.

Join the GlobalSecurity.org mailing list

Page last modified: 07-09-2013 19:24:52 ZULU