3-inch/23-caliber gun

The 3-inch/23-caliber gun (spoken "three-inch-twenty-three-caliber") was the standard anti-aircraft gun for United States destroyers through World War I and the 1920s. United States naval gun terminology indicates the gun fired a projectile 3 inches (76 mm) in diameter, and the barrel was 23 calibers long (barrel length is 3" × 23 = 69" or 1.75 meters.)

Description
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.

History
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.

A partially retractable version was mounted as a deck gun on the US L-class, USS M-1 (SS-47), AA-1-class submarine, 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 When World War II began, the 3"/23-caliber gun was outdated, and surviving United States destroyers built during the World War I era that were armed with the 3"/23-caliber were rearmed with dual-purpose 3"/50-caliber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:


 * AA-1-class submarines
 * Active-class patrol boats
 * Aylwin-class destroyers
 * Caldwell-class destroyers
 * Colorado-class battleships
 * Clemson-class destroyers
 * Dubuque-class gunboats
 * Florida-class battleships
 * Klondike-class destroyer tenders
 * L-class submarines
 * USS M-1 (SS-47)
 * O-class submarines
 * PGM-1-class motor gunboat
 * SC-1-class submarine chasers
 * SC-497-class submarine chasers
 * Wickes-class destroyers