Its secondary armament consisted of an air-cooled .50 in (13 mm) M2 machine gun for local defense.

It was powered by a White 160AX, 147 hp, 386 in3, six-cylinder gasoline engine with a compression ratio of 6.3:1.

[1][2] In the autumn of 1941, when the Armored Force expanded, an urgent need for self-propelled artillery arose.

However, the urgency of the requirement resulted in the approval by the Adjutant General and the construction of a prototype was authorized by OCM 17391, dated 31 October 1941; the new vehicle designated as the 105 mm howitzer motor carriage T19.

[3][4][5] As with other American self-propelled guns produced during the early World War II period, the prototype was assembled and tested at the Aberdeen Proving Ground.

[7][8][9] The T19 HMC was designed as a stopgap measure until better self-propelled artillery pieces were made; it served in the Tunisia Campaign in North Africa in 1942–43.

It was employed mainly in most battalions' headquarter platoons, and the "cannon companies" of infantry divisions.

[a] The T19 was soon replaced in armored divisions by the M7 Priest, a 105 mm howitzer on a fully tracked chassis.