3 inch/23 caliber gun

The 3"/23-caliber cannon was the first purposely designed anti-aircraft cannon to reach operational service in the US military, and was a further development of a 1-pounder cannon concept designed by Admiral Twining to meet the possible threat from airships being built by various navies. It entered service in late 1913 on the Aylwin-class destroyers. A partially retractable version was mounted as a deck gun on the US L-class, M-1 (SS-47), AA-1 class, and O-class submarines. When World War II began, the 3"/23-caliber gun was outdated, and surviving United States destroyers built during the World War I era that were armed with the 3"/23-caliber were rearmed with dual-purpose 3"/50-caliber guns. Where there was no air threat during World War II, the 3"/23-caliber gun was employed in the surface-to-surface role for use against submarines, and was mounted on submarine chasers, armed yachts, and various auxiliaries. Some major warships carried 3"/23-caliber guns temporarily while awaiting installation of quad 1.1"/75-caliber guns. The 3"/23-caliber gun was mounted on:

The built-up gun with horizontal sliding breech block weighed about 531 pounds (241 kg) and used fixed ammunition (case and projectile handled as a single assembled unit) with a 13-pound (6 kg) projectile at a velocity of 1650 feet per second (500 m/s). Range was 10,100 yards (9235 meters) at 45 degrees elevation. Ceiling was 18,000 feet (5500 meters) at the maximum elevation of 75 degrees.