This gun was cocked with external cocking levers on the side of the breech. The SR9 is recoil operated with a locked breech. The barrel is integrated with the barrel breech. The barrel was a wire wound A tube in a jacket with a screw breech. The barrel is a forging screwed into the breech mechanism. This gun automatically cocked itself when the breech was closed. The hammer is cocked when the breech is opened. Each barrel is a very simple non-automatic design having its own breech and bolt. The gun had problems with cracks developing near the breech after repeated firing. Each 5-inch/38 gun weighed almost without the breech; the entire mount weighed . It is a automated-action gun with vertical block breech. Each gun weighed about without the breech, or with the breech. Each gun weighs about without the breech, or with the breech. It used a Welin interrupted screw breech. The weakness of the breech-loader was the obvious problem of sealing the breech.