US 8in Gun in Aschaffenburg, Bavarian
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The 8in Gun M1 was produced alongside the 240mm Howitzer M1, and fired a lighter shell to a longer distance. It saw service in the later part of the Second World War, being used in Italy, North-Western Europe and the Philippines.
The 8in Gun M1 was notable as the only piece of heavy artillery used by the US Army during the Second World War that hadn’t been produced to replace a First World War era equivalent. It had been suggested by the Westervelt Board of 1919, which suggested that an 8in gun with a range of 35,000 yards (32,110m) would be useful.
The first attempt to satisfy this requirement began in 1920, and was an attempt to produce a road mobile version of the coast-defence 8in railway gun. This weapon could only reach 24,000 yards, and the project was abandoned in 1924.
In 1939 work resumed on a plan to produce a new 240mm howitzer. It was suggested that the same carriage could carry the 8in gun, and work on this project began in June 1940, as the 8in Gun T2. The new gun was 50 calibres long, and had a muzzle velocity of 2,800ft/ sec with a 106lb propellant charge. This caused excessive barrel wear, and accuracy rapidly reduced. The long barrel also proved to be unstable on its transport trailer.
A number of experimental versions were produced in an attempt to reduce barrel wear, but without success.
The T2E1 used the British Probert rifling system. The normal 8in shells had a single driving band, designed to fit into the rifling. The Probert system added a second band towards the front of the shell.
The T2E2 used a different rifling twist to the standard T2.
The T2E3 had a chromium plated bore in an attempt to reduce barrel wear.
The T2E4 combined the Probert system and the chromium plating.
The T2E5 used pre-engraved projectiles.
The T2 was eventually standardised in January 1944 as the 8in Gun M1, despite the known flaws. It had longer range than the howitzer (33,635 yards compared to 22,225 yards), but fired a lighter projectile (shared with an 8in coastal artillery gun and an 8in naval cruiser gun). It was quite time consuming to assemble the gun, ideally requiring a crane to lower the gun onto the carriage.
Although the 8in Gun had been designed to use the same carriage as the 240mm howitzer, the different weight of the gun and recoil forces meant that it needed a different equilibrator and recoil system. The equilibrator used pressured nitrogen, which was carried in a tank below the barrel.
Production began Nov 42, standardised as 8in Gun M1 on carriage M2 in Jan 44
Production of the 8in gun began in November 1942.Only 10 were built that year, followed by 49 in 1943, 57 in 1944 and 23 in 1945, for a total of only 139.
The 8in gun was rushed into action in Italy early in 1944 to cope with the long range German 170mm guns that were threatening the Anzio beachhead. Two went to Anzio and two to Cassino, where it proved to be a very successful weapon, providing a useful counter-battery ability.
Only eight 8in battalions were formed, five serving in Europe and three in the Pacific. The guns that went to the Pacific were used on the Philippines.
Nine guns went to the US 1st Army, and fired 18,935 rounds between D-Day and VE Day.
Seventeen went to the British under Lend Lease.
After the end of the war the American guns were put into storage, but they were never reactivated.
Name |
8in Gun M1 |
Calibre |
8in |
Barrel Length |
L/50 |
Weight for transport |
|
Weight in action |
31.4 tonnes (34.6 tons) |
Elevation |
To 50 degrees |
Traverse |
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Shell Weight |
240lb (108kg) M103 HE |
Muzzle Velocity |
2,800ft/ sec |
Maximum Range |
35,000 yards (32km) |
Rate of Fire |
1 round per minute |