3-inch/23-caliber gun
              < 3-inch 
 
            
          | 3"/23 caliber gun | |
|---|---|
| A 3"/23-caliber gun being fired aboard the United States Navy submarine chaser USS SC-291 sometime between 1918 and 1920. | |
| Type | |
| Place of origin | United States | 
| Service history | |
| In service | 1913—1946 | 
| Used by | US Navy | 
| Wars | World War I World War II | 
| Production history | |
| Manufacturer | 
 | 
| Variants | Mark 9, 13, and 14 | 
| Specifications | |
| Mass | 
 | 
| Length | 
 | 
| Barrel length | 
 | 
| Shell | 16.5 lb (7.5 kg) 76.2x234 mm R | 
| Caliber | 3-inch (76 mm) | 
| Elevation | -15° to +65° or +75° | 
| Traverse | 365° | 
| Rate of fire | 8 – 9 rounds per minute | 
| Muzzle velocity | 1,650 feet per second (500 m/s) | 
| Effective firing range | 
 | 
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.)