- Yes
- No
Hello and welcome to the suggestion for the T48 Gun Motor Carriage! This is an M3 half-track equipped with the 57 mm M1 anti-tank gun, currently found in the Soviet tree as a premium under the name of SU-57. While the Soviet Union was undoubtedly the largest user of this vehicle, I would like to suggest it for the nation that built it and technically operated it. I say technically because the U.S. Army at one point had nearly 300 T48s, but would convert all but one into regular M3 half-tracks. In War Thunder, the T48 GMC would give the U.S. tree the excellent 57 mm M1 gun, capable of being used alongside the M3 Medium and M5A1 Light tanks at 2.3 battle rating.
History
A T12 GMC (later known as M3 GMC) at Aberdeen Proving Ground, November 29th, 1941.
By 1941, much of Western Europe had been taken over by Germany, who had effectively employed its armor in a doctrine known as Blitzkrieg. Across the Atlantic, the United States began to study in-depth this tactic, deciding to counter such a mechanized force with ‘anti-mechanized’ units on self-propelled mounts, with heavy emphasis on visibility, mobility, and heavy armament. The armament would likely be the 75 mm M1897 field gun, a modernized version of the famous “French 75” used to great success in the last World War. At the same time, the M3 half-track was entering service, and the U.S. Army’s Ordnance Department and Assistant Chief of Staff agreed on mounting the M1897A4 on the M3 as an ‘expedient tank destroyer.’
The result of this was the T12 Gun Motor Carriage, and by September of 1941, 86 had been ordered and delivered, with the initial order of 36 going to the team at Aberdeen Proving Ground in Maryland and the 93rd Antitank Battalion for field testing. The other 50 were shipped to the Philippines to defend against the Japanese invasion, which was something of an anomaly given the vehicle had only been conceived six months prior. The T12 was soon redesignated as the 75 mm Gun Motor Carriage M3, and would see increasing use through the war.
A 6-pounder portée in use by the New Zealand 7th Anti-Tank Regiment in El Alamein, Egypt, October 1942.
With the successful employment of the M3 GMC, the Ordnance Corps recommended Ordnance Directive OCM 18099 for the development of the 57 mm Gun Motor Carriage T48 based on the M3 GMC. This was initially intended for the United Kingdom as part of the Lend-Lease program, utilizing its best anti-tank weapon at the time, the 6-pounder anti-tank gun. To be used were the Mark III and Mark V versions, the latter of which the United States license produced as the 57 mm gun M1. The main difference between the Mark III and Mark V variants was the barrel, with the Mark V having a slightly longer, thin walled barrel. While the Mark III was installed on the pilot vehicle, the Mark V was slated for use on production vehicles.
Assembly of the T48 began in May of 1942 at Aberdeen Proving Ground, where the 57 mm gun was mounted in the M12 recoil mechanism and installed in a tubular pedestal using the top portion of the M1 field carriage for the 57 mm gun. To simplify production, the original pedestal was replaced with a conical structure designated 57 mm gun mount T5. As with the M3 GMC, the gun was aimed forward, mounted behind the driver’s compartment, and could traverse 55°, and elevate up to 15°, and down -5°. The vehicle seated a crew of five, the driver and radio operator in the front, and loader, gunner, and commander in the rear behind the gun shield. The gun shield from the T44 Gun Motor Carriage was briefly installed on the T48 to expedite the testing phase, with a new one designed for the T48 being installed shortly after, comprised of 5/8 inches in front, and 1/4 inch thick on the sides and top. Due to experience with the muzzle blast and recoil deforming the hood of the vehicle on the M3, demountable headlights and reinforced angles on the hood plates were added. Due to the original M3 GMC’s travel lock proving unsatisfactory for the 6-pounder, a travel lock was also installed on the hood of the vehicle.
The T48 GMC pilot at Aberdeen, circa August 1942.
After further testing at Aberdeen, production of the 57 mm Gun Motor Carriage T48 began in December of 1942 at the Diamond T automobile company. By the end of production in May of 1943, 962 had been built, and the British had ordered 680 by this point, intending to use them in North Africa, but by the time they arrived in the summer, the last Axis forces in Tunisia had surrendered or retreated, and the British did not consider the T48 suitable for use in the European theater. Regardless, 30 were accepted into service, and modified with the Wireless Set No.19 radio, but were never used in combat, later being converted into Armored Personnel Carriers. The United States Army took possession of the remaining 282, but similarly to the British, would convert nearly all of these to regular M3 half-tracks in 1944, with the exception of one, which seems to have seen service overseas with the Army. Due to it not being originally intended for the U.S. Army, the Ordnance Department would list the T48 as a limited procurement item.
Although this was the end for the T48 GMC with the Western Allies, the Soviet Union was more than happy to accept them. By the second half of 1944, the Soviet Union had taken possession of the 650 T48s intended for the British, now indexed as the SU-57 15 of which would go to the Polish Armed Forces in the East. The Soviets would form three SU-57 brigades of their own in Moscow attached to the 1st Ukrainian Front in July of 1944, and of these three, the 16th Brigade went to the 3rd Guards Tank Army, the 19th to the 1st Guards Tank Army, and the 22nd to the 4th Tank Army. All three would fight in the Lvov-Sandomierz Offensive, intended to repel the Germans from Eastern Poland and Ukraine. While the 19th Brigade would later be transferred along with the 1st Guards Tank Army to the 1st Belorussian Front, the other two would take part in the offensives on Prague and Berlin. Aside from these three brigades, the SU-57 would also be issued to independent motorcycle regiments and battalions, and fill in the role of the SU-76M in three medium self-propelled gun brigades in December 1944. By the end of the war, 212 SU-57s had been written off.
An SU-57 (T48 GMC) in Prague, May 9th, 1945.
Specifications
Crew: 5
Mass: 9.4 t
Length: 6.4 m
Width: 2.1 m
Height: 2.1 m
Armament: 57 mm gun M1
Ammunition stowed: 99 rounds
Engine: 148 hp White 160AX gasoline engine
Maximum speed: 72 km/h
Maximum range: 240 km
Sources
- Hunnicutt, R. P. (2001) Half-Track: A History of American Semi-Tracked Vehicles. Navato, CA. Presidio Press.
- Green, Michael (2014). American Tanks and AFVs of World War II. Oxford, UK. Osprey Publishing.
- Tank Archives: Lend Lease Tank Destroyer
