A disappearing gun (often called a disappearing carriage) is a type of heavy (mainly coastal) artillery for which the gun carriage enabled the gun to rotate backwards and down into a pit protected by a wall (the parapet) or a bunker after it was fired. This retraction lowered the gun from view by the enemy while it was being reloaded.
Military - Hardware Static Display
It also made reloading easier, since it lowered the breech to a level just above the loading platform, and shells could be rolled right up to the open breech for loading and ramming. Although it had these advantages, the disappearing carriage was also a complicated mechanism. In the U.S., disappearing carriages were mostly withdrawn from active service by the early 1920s.
These 10-inch (25-cm) seacoast artillery guns on their carriages were salvaged in the mid-1960's from their final active duty location at Fort Wint on the U. S. Naval Base Subic Bay. The guns showed visible shrapnel scarring from the effects of the Japanese bombings in the Philippines at the opening of World War II.