T19 Howitzer Motor Carriage

The T19 Gun Motor Carriage (HMC), was a World War II United States Army self-propelled gun mounted on a half-track chassis. It was equipped with a 105 mm howitzer and an air-cooled .50 in cal M2 machine gun mounted coaxially to the howitzer. It was produced by Diamond T between January 1942 to April 1942.

It served in the North African Campaign, while a couple served in the Sicilian Campaign, the Italian Campaign, and even as late as the Invasion of southern France.

Specifications
The T19 Howitzer Gun Motor Carriage was similar to those of the M3 Half-track. The T19 was 20 ft 2 in long, 6 ft 5 in wide, 7 ft 8 in high, with a weight of 9.54 short tons. The suspension consisted of a semi-elliptical longitudinal leaf spring for the wheels and vertical volute springs for the tracks. Powered with a White 160AX, 147 hp, 386 in3, 6 cylinder petrol engine with a compression ratio of 6.3:1, itwas capable of a maximum road speed of 45 mph. The power to weight ratio is 14.7 hp/tonne. The vehicle is of operated by a crew of 6 with armor as thick as half an inch. The armament consisted of 1 105 mm M2A1 howitzer and a .50 cal M2 Browning machine gun.

Development


In the autumn of 1941, when the Armored Force expanded, an urgent need for self-propelled artillery arose. Although a full-track chassis were preferred, the situation required the use of whatever vehicles were immediately available. Once again, the job fell for the M3 halftrack and it was selected to carry a 105 mm M2A1 howitzer. Although this design had originally been suggested in September 1941, it had been disapproved. However, the urgency of the requirement resulted in the approval by Adjutant General and the construction of a pilot was authorized by OCM 17391, dated 31 October 1941. This action designated the new vehicle as 105 mm howitzer motor carriage T19.

As with other American early-World War II self-propelled gun pilots it was assembled and tested at Aberdeen Proving Grounds, and used the M2 recoil machanism and other parts of the M2 carriage. After several tests, the gun carriage proved fragile on bumpy terrain. The problem was corrected by reinforcing the frame, and redesigning the howitzer mount. Demountable headlights were recommended because of the muzzle blast, although they were unavailable for earlier production models. Earlier models had no shield for the howitzer but they later added a foldable shield during testing. The gun was facing forward, like many other halftrack models. The total traverse was 40 degrees and the elevation was from +35 to -5 degrees. The armored windshield cover was remounted so it could fold onto the hood. After further testing, it was accepted for production.

After it was accepted, a pilot was shipped to Diamond T as a guide for production. The first production vehicle was delivered to the US Army in January 1942. A total of 324 T19s were produced when production ended in April 1942

Service history
The T19 HMC was designed as a stopgap measure until better self-propelled artillery pieces were made, it served in North Africa with a few serving in Sicily, Italy, and even as late as the Invasion of southern France (Operation Dragoon). It was retired after other pieces of self-propelled artillery were made (like the M7 Priest). It was finally declared obsolete by OCM 28557, dated 26 July 1945. That month the contractor Brown & McLaughlin converted 90 T19s into M3A1 Halftracks.