3"/50 Caliber Gun - Earlier Guns

Earlier Guns

The 3"/50 caliber gun (Mark 2) was an early model with a projectile velocity of 2,100 feet (640 m) per second. Low-angle mountings for this gun had a range of 7000 yards at the maximum elevation of 15 degrees. By World War II these guns were found only on a few Coast Guard cutters and Defensively Equipped Merchant Ships.

Low-angle 3"/50 caliber gun (Marks 3, 5, 6, and 19) were carried by submarines, auxiliaries, and merchant ships during the second world war. These guns fired the same 2,700 feet (820 m) per second ammunition used by the following dual purpose Marks, but with range limited by the maximum elevation of the mounting. These were built-up guns with a tube, partial-length jacket, hoop and vertical sliding breech block.

Dual-purpose 3"/50 caliber gun (Marks 10, 17, 18, and 20) were mounted in fleet submarines and replaced the original low-angle 4"/50 caliber guns (Mark 9) to provide better anti-aircraft protection for "flush-deck" Wickes and Clemson class destroyers during World War II. The AVD seaplane tender conversions received 2 guns; the APD transport, DM minelayer, and DMS minesweeper conversions received 3 guns, and those retaining destroyer classification received 6. These guns used fixed ammunition (case and projectile handled a single assembled unit) weighing 34 pounds. Projectiles weighed about 13 pounds including a burster charge of 0.81 pounds for Anti-aircraft (AA) rounds or 1.27 pounds for High Capacity (HC) rounds. Maximum range was 14,600 yards at 45 degrees elevation and ceiling was 29,800 feet (9,100 m) at 85 degrees elevation. Useful life expectancy was 4300 effective full charges (EFC) per barrel.