Disappearing Gun: This was most common design for heavy coast guns from 1890 to 1917. Theses guns were mounted on moving arms which had a counterweight at the other end. When the counterweight was released after loading, the gun would be lifted to a firing position.  The recoil after firing would move the gun back down to the loading position. The disappearing gun was produced in 16-, 14-, 12-, 10-, 8-, and 6-inch calibers.