The 16"/50 Mark 7 - United States Naval Gun was originally intended to fire the relatively light 2,240 pound (1,016 kg) Mark 5 armor piercing shell, the shell handling system for these guns was redesigned to use the "super-heavy" 2,700 pound (1,225 kg) APC Mark 8 before any of the USS Iowa class battleships were laid down. This heavier projectile made these guns nearly the equal in terms of penetration power to the 460 mm (18.1 in) guns of the Japanese Yamato class battleships yet they weighed less than three-quarters as much.

The weapon is constructed of liner, A tube, jacket, three hoops, two locking rings, tube and liner locking ring, yoke ring and screw box liner. Some components were autofretted. As typical of United States naval weapons built in the 1940s, the bore was chromium plated for longer barrel life. Uses a Welin breech block that opens downwards and is hydraulically operated. The screw box liner and breech plug are segmented with stepped screw threads arranged in fifteen sectors of 24 degrees each.

Gun Characteristics