13"/35 caliber gun

The 13"/35 caliber gun Mark 1 (spoken "thirteen-inch-thirty-five-caliber") was used for the primary batteries on eight of the first nine battleships in the United States Navy,, and ; USS Iowa (BB-4) used 12"/35 caliber guns.

The Navy's Policy Board called for a variety of large caliber weapons in 1890, with ranges all the way up to 16 in. A 16-inch caliber gun was beyond the US manufacturing capabilites at this time though and the largest gun possible was the 13"/35 caliber. The Navy intended to use this gun in short-range action against heavily armored targets and was fitted to the first true battleship in the US Navy, USS Indiana (BB-1). This turned out to be the only 13-inch gun developed for the US Navy.

Design
The 13-inch Mark 1 was a built-up gun constructed in a length of 35 caliber, Mod 0 and Mod 1. The Mod 0 had a tube, jacket, and nine hoops while the Mod 1 had a nickel-steel liner and only eight hoops. The Mark 2, was of similar construction as the Mark 1 Mod 0 but had only seven hoops and two locking ring. Two Mark 2 guns, Nos. 23 and 33, were converted into experimental guns. The first, No. 23, was converted in 1923 into a 16"/28.8 caliber Mark A Mod 0 experimental gun. The barrel was bored out to 16 in and hooped to the muzzle. The gun was tested a total of seven times in July 1923 but then set aside until 1956. The gun was used for bomb tests between October and December 1956 and fired another 19 times. This gun is now on display at the Naval Surface Warfare Center in Dahlgren, Virginia. The other Mark 2, No. 33, was also bored out, but only to 14 in, sometime prior to 1923 and again used as an experimental gun, this one at Plate Battery. In 2005 it too was still located at the NSWC, Dahlgren.