Testing of single and twin mounted 3“/50 caliber Mark 22 semi-automatic anti-aircraft guns in 1951

In 1944-1945, the USN found that their 20 mm Oerlikons and 40 mm Bofors batteries were ineffective in stopping Japanese Kamikaze attacks. Only the 5“/38 (12.7 cm) fired a round large enough to kill-stop a determined attacker and this weapon was too heavy to use in the numbers necessary. This problem led to an accelerated program to develop an intermediate-caliber weapon that could fire a VT fuzed shell. The weapon chosen was the standard 3“/50 ( cm) Mark 22 which was used on many Destroyer Escorts and auxiliaries built during the latter part of World War II. This was the smallest-caliber weapon which could still use the VT fuzes available at the time. It also had a concentric counter-recoil spring, which meant that it was more easily adapted for automatic fire. Automatic fire was achieved with an electrically driven auto-loader using revolving sprockets. BuOrd rushed this through the design phase, with the first prototype being ready for test firing on 1 September 1945. The end of the war