6"/53 caliber gun

The 6"/53 caliber gun (spoken "six-inch-fifty-three-caliber") formed the main battery of United States Navy light cruisers and submarine cruisers built during the 1920s. United States naval gun terminology indicates the gun fired a projectile 6 inches (15 cm) in diameter, and the barrel was 53 calibers long (barrel length is 6 inch x 53 = 318 inches or 8 meters.)  The gun with side swing Welin breech block and Smith-Asbury mechanism weighed about 10 tonnes and used a silk bag containing 44-pounds (20 kg) of smokeless powder to give a 105-pound (47.6 kg) projectile a velocity of 3000 feet per second (900 m/s).  Early Marks were built-up guns with a liner, tube, full-length jacket, and 2 hoops; but the Mark 14 gun was of monobloc construction.  Useful life expectancy was 700 effective full charges (EFC) per liner.

Mark 13 casemate mounting
These guns were intended for the secondary battery of the s and South Dakota-class battleships. They were installed in s when the intended ships were canceled under provisions of the Washington Naval Treaty. Maximum range was 21000 yd at the maximum elevation of 20 degrees.

Mark 16 turret mounting
This two-gun turret was a design modification to improve the range and broadside of the Omaha-class cruisers. Maximum range was 25300 yd at the maximum elevation of 20 degrees.

Mark 17 wet mounting
These single open mounts were installed fore and aft of the conning tower on USS Argonaut (SM-1), USS Narwhal (SS-167), and USS Nautilus (SS-168). Maximum range was 23300 yd at the maximum elevation of 25 degrees.