T30 Howitzer Motor Carriage

The T30 Howitzer Motor Carriage (HMC) was a United States Army self-propelled gun used in World War II. Its design was based on requirements for an assault gun issued by the Armored Force in 1941 and it was built as an interim solution until a fully tracked design was complete.

Produced by the White Motor Company, the vehicle was simply a 75 mm Pack Howitzer M1 mounted on modified a M3 Half-track that had had its fuel tanks moved to the rear. It was first used in combat in the North African Campaign in November 1942. Some were later leased to French forces and the type was used as late as the First Indochina War in the 1950s.

T30 Howitzer Motor Carriage
Class Vehicle
Type Self-Propelled artillery
Manufacturer White Motor Company
Origin United States of America
Country Name Origin Year
United States of America 1942
Country Name Operational Year Retirement Year
France 1942 View
United States of America 1940 View
ManufacturerName Production From Production To Quantity
White Motor Company 1942 500 View

Based on the M3 Half-track, the T30's specifications were similar to its parent vehicle. It was 20 ft 7 in (6.28 m) long, 6 ft 5 in (1.96 m) wide, 8 ft 3 in (2.51 m) and high, and weighed 10.3 short tons (9.3 t). The suspension consisted of vertical volute springs for the tracks and leaf springs for the wheels, while the vehicle had a fuel capacity of 60 US gallons (230 l). It had a range of 150 mi (240 km) and had a speed of 40 mph (64 km/h), and was powered by a White 160AX, 147 hp (110 kW), 386 in3 (6,330 cc), six-cylinder, gasoline engine, with a compression ratio of 6.3:1. It had a power-to-weight ratio of 15.8 hp/ton.

Gun specifications

The T30's main armament was a short barreled 3.0 in (75 mm) pack howitzer. The 75 mm Pack Howitzer M1 as mounted could depress nine degrees, elevate 50 degrees, and traverse 22.5 degrees to each side. The vehicle had stowage for sixty rounds of 75 mm ammunition, and although it was not designed for anti-tank use, it had a high explosive anti-tank (HEAT) shell that could penetrate 3 in (76 mm) of armor at normal ranges. The gun shield had 0.375 in (9.5 mm) thick armor, designed to stop a .30 cal (7.62 mm) bullet from 250 yards (230 m) away.


The T30 HMC was originally conceived in 1941 as an interim design to fulfil the Armored Force's requirement for an assault gun to equip tank and armored reconnaissance units. The Ordnance Department design was based on the M3 Half-track in order that it could be brought into service quickly. The pilot vehicle was authorized in October 1941 armed with an M1A1 75 mm Pack Howitzer and its mounting designed to fit on a simple box structure in the back of an M3 Half-track.

Authorization for production of two pilot vehicles was made in January 1942; first deliveries of the vehicle were made the following month from the White Motor Company. As it was seen as a temporary solution it was never given type classification. In September 1942, the T30 was partially replaced by the Howitzer Motor Carriage M8 (the same gun on an M3 Stuart). After that, it was declared as "limited standard". Around 500 were produced, all by the White Motor Company.

The T30 HMC entered service in November 1942, seeing action for the first time in the North African Campaign. In the 1st Armored Division, each armored regiment was issued twelve T30s. Of these, three were used in each battalion headquarters platoon and three were used in each regimental reconnaissance platoon. In addition, the 6th and 41st Armored Infantry Regiments were each issued with nine T30 HMCs, with three of them being allocated to the headquarters platoon in each armored infantry battalion. Most infantry divisions in the North African Campaign deployed a "cannon company" equipped with six T30s and two 105 mm T19 HMCs. In one encounter in North Africa, the T30 was used in an attempt to destroy German tanks. Although the T30s fired several volleys, the German tanks were barely damaged. After the T30s fired and the result became clear, they were ordered to retreat under the cover of smoke. After several similar occasions, the U.S. Army learned that they should not put self-propelled howitzers or mortars into direct combat with tanks.

The T30 also served during the Allied invasion of Sicily in 1943, the war in Italy in 1944, and possibly in the Pacific. It was removed from infantry division use in March 1943, following changes in the organization of US infantry battalions, and was replaced by towed howitzers. The T30 was eventually replaced by the M8 HMC, which was based on the M5 Stuart light tank, and which began entering service around the same time as the T30. Only 312 T30 HMCs were delivered in their original configuration, as the last 188 were converted back into M3 Half-tracks before they were delivered. Later on, the US leased several to French forces and some were used as late as the First Indochina War before the vehicle was retired from service in the 1950s.

Type Self-propelled artillery
Place of origin United States
Service history
In service 1942–50s
Used by United States
Wars World War II
First Indochina War
Production history
Designer Ordnance Department
Designed 1941
Manufacturer White Motor Company
Produced 1942
Number built 500
Weight 10.3 short tons (9.3 t)
Length 20 ft 7 in (6.28 m)
Width 6 ft 5 in (1.96 m)
Height 8 ft 3 in (2.51 m)
Armor up to 0.375 in (9.5 mm)
M1 Pack Howitzer
Engine White 160AX, 386 in3 (6,330 cc), 6-cylinder, gasoline engine,compression ratio 6.3:1
147 hp (110 kW)
Power/weight 15.8 hp/ton
Suspension Vertical volute springs for tracks, leaf springs for the wheels
Fuel capacity 60 US gal (230 l)
Speed 40 mph (64 km/h)

End notes