7"/44 caliber gun

The 7"/44 caliber gun Mark 1 (spoken "seven-inch-forty-four--caliber") and 7"/45 caliber gun Mark 2 (spoken "seven-inch-forty-five--caliber") were used for the secondary batteries of the United States Navy's last generation of pre-dreadnought battleships, the and. The 7 in caliber was considered, at the time, to be the largest caliber weapon sutiable as a rapid-fire secondary gun because its shells were the heaviest that one man could handle alone.

Design
The 7" Mark 1 was built in a length of 40 calibers, had a nickel-steel liner, with a tube, jacket and three hoops with a locking ring, all made of gun steel, a screw box liner, and Welin breech block. The Mark 1 was hooped from the breech to 47.5 in from the muzzle. Only one Mark 1 was built, the prototype. The Mark 2 was the production version, it was of the same construction as the Mark 1 except that it was hooped all the way to the muzzle and had one caliber, or 7 in, added to its length. The Mark 2 Mod 1 was constructed with a conical nickel-steel liner. Two experimental Mark 2 guns, given serial numbers 2 and 3, were built with wider diameter breech ends, with S/N 2 modified with a conical nickel-steel liner and modified breech, becoming Mark 2 Mod 2.

Most of the 7-inch guns were removed before WW I and mounted on tractors that had been designed by the Bureau of Ordnance (BuOrd) and built in Philadelphia by the Baldwin Locomotive Works. The Marines ordered 20 of these guns, with the Army ordering 34, however, before the Armistice was signed only 18 of them were delivered to the Marines and 20 to the Army.

The Army had requested these guns because of their lack of heavy artillery in France. The 20 guns for the Marines were to go to the new 10th Marine Artillery Regiment, that was training at Quantico, Virginia, in the fall of 1918. The Marines fired the first shot at Lower Station, Naval Support Facility Dahlgren today, 24,000 yds down the Potomac River on 16 October 1918. In 1920 the BuOrd described the weapon as, "the heaviest and hardest hitting gun for which a mobile field mount of this kind had ever been requested by any nation or army." The gun and tractor is the ancestor of the self-propelled artillery that has played a major roll in most wars since.

Due to the emergency situation at the beginning of WW II several of these guns were pressed into service as coastal defense batteries.

Survivors

 * Fort DeRussy, Honolulu, Hawaii
 * Bora Bora, French Polynesia
 * Naval Surface Warfare Center Dahlgren, Dahlgren, Virginia