Presumably inspired by the German "Paris Gun" of World War I, this experimental weapon was converted from a 14"/50 (35.6 cm) gun by lengthening it with a hoop of alloy steel to 900 inches (22.860 m) and installing a heavy alloy-steel liner. The chamber volume was equivalent to that used for the 14" (35.6 cm) guns and the rifling was to be increasing RH from 1 in 48 to 1 in 45. Weight with breech block was 209,429 lbs. (94,996 kg). This weapon was designed to fire a 275 lbs. (125 kg) projectile at a muzzle velocity of 5,000 fps (1,524 mps). The gun was almost completely finished except for the rifling when the project was cancelled about 1919.

A reduced-scale version of this weapon was the 3"/105 (7.62 cm) Mark 16.

Additional Pictures


"US Naval Weapons" by Norman Friedman
"A Treatise on Rifling of Guns" by Carl F. Jeansén
Special help from Leo Fischer and James P.

Page History

30 October 2006 - Benchmark
01 February 2016 - Added information about other guns in the photographs
25 July 2016 - Converted to HTML 5 format