| Railway gun|
1925 to 1946
World War II
| United States|
The 14-inch M1920 railway gun was the last large caliber railway gun to be deployed by the United States Army. It was an upgrade of the US Navy 14"/50 caliber railway gun.
14-inch M1920 railway gun Wikipedia
After the close of World War I, the US Army wanted to incorporate the lessons learned from other railway gun mounts and fulfill coastal artillery requirements for hitting a moving target. An effort to design a more universal mount for the Navy's Mk. IV 14"/50 caliber gun was undertaken.
The primary difference from the earlier Navy versions lies in the M1920 carriage, which could be raised and lowered. Prepositioned fixed mounts were installed at the forts, and the gun's rail trucks could be taken out from under the frame. After the removal of the rail trucks, the gun was lowered and bolted onto a pivot point for rapid 360 degree movement, necessary for tracking ships in coast defense. The M1920 carriage made the gun much more flexible. It allowed for the standard practice of using a curved piece of rail to traverse the gun, and it enabled the gun to be used in a fixed position.
Two guns were deployed to Fort MacArthur. The remaining two guns were deployed to Fort Grant and Fort Randolph in the Panama Canal Zone. The two guns deployed to the Panama Canal Zone could be moved to either coast on the Panama Canal Railway.
The Mk.IV gun was manufactured in two models:M1920MI centerline of breechblock mechanism canted 16 degrees counterclockwise to fit recoil band
M1920MII breech mechanism is set straight in relation to axis of tube.
The following sighting equipment was used with the gun:M1 fire adjustment board
M1 plotting and relocating board
M1A1 range correction board
M7 spotting board
M1A1 height finder
M1910 azimuth instrument
M8 helium filling kit
M1 gunners quadrant
M1918 aiming rule
M1 prediction scale
firing tables- 14-m-1, 14-e-3, 14-g-2.
M1917MI panoramic telescope
M1922 panoramic telescope
M1 generating unit (mounted on the forward railway truck)
M1 powder car
M1 projectile car
M2 fire control car
M1918 repair car
All four guns were cut up for scrap in 1946.