12-inch/50-caliber Mark 7 gun

12"/50 caliber Mark 5 Naval Gun USS Arkansas Main Guns Firing.jpg Arkansas BB-33 firing her 12"/50 guns in battle practice prior to World War I United States Naval gun YES YES 1912-1952 * United States Navy Argentine Navy *World War I World War II Bureau of Ordnance 1910 *U.S. Naval Gun Factory Bethlehem Steel *Mod 0: 28 (Nos. 180–182, 186–210) Mod 2: 3 (Nos. 183–185) Mod 3: 6 (Nos. 211–216) Export: 25 (Nos. 795–817, 919–920) Mods 0–19 *121489 lb kg (without breech) 123160 lb kg (with breech) 50 ft 7.25 in m 2 49 ft 6.25 in m 2 bore (49.5 calibers) 870 lbarmor-piercing 12 in 0 2–3 rounds per minute *2900 ft/s (full charge) 2100 ft/s (reduced charge) 23900 yd at 15° elevation -5° to +15° −150° to +150° The 12"/50 caliber Mark 7 gun (spoken "twelve-inch-fifty-caliber") was a United States Navy's naval gun that first entered service in 1912. Initially designed for use with the Wyoming battleship 4 of dreadnought battleships, the Mark 7 also armed the Argentine Navy's Rivadavia battleships.Navweaps 2016Friedman 2011 172–173 Design and development The 12 in on out 0/50 caliber Mark 7 naval gun was only a slight improvement over the preceding American naval gun, the 12"/45 caliber Mark 5 gun. As such, it was a very similar weapon, having been lengthened by five calibers to allow for improved muzzle velocity, range, and penetrating power. Designed to the specifications of the Bureau of Ordnance, the Mark 7 was constructed at the U.S. Naval Gun Factory in Washington, D.C.Navweaps 2016Friedman 2011 172–173DANFS 2015 The Mark 7 weighed 124140 lb with the breech and was capable of firing two to three times a minute. At maximum elevation of 15° it could fire an 870 lb shell approximately 20000 yd. With an initial muzzle velocity of 2900 ft/s, the gun had a barrel life of 200 rounds, and was capable of firing either armor piercing or Common projectiles.Navweaps 2016Friedman 2011 172–173 As designed, the Mark 7 was capable of penetrating 17.4 in of Harvey plated side armor at 6000 yd, 14.7 in at 9000 yd, and 12.3 in at 12000 yd.Navweaps 2016 By comparison the 12"/45 caliber Mark 5 it replaced could penetrate 16.6 in, 12.2 in, and 9.9 in at those distances, respectively.Navweaps2 2016 Bethlehem Steel built the first gun, No. 180. Mod 0, Nos. 181, 182, and 186–200, was a built-up gun consisting of a tube, jacket, and eight hoops, a screw-box liner with locking hoops and rings and hand operated and Smith-Asbury mechanism. The gun was constructed with nickel-steel and hooped to the muzzle.Friedman 2011 172–173 Mod 1 was gun No. 180, rebuilt into gun No. 180L, with its chase hoops rebuilt along with a new conical nickel-steel liner, a smaller chamber, and the rifling increased.Friedman 2011 172–173 Mod 2, gun Nos. 183–185, was a Mod 0 gun relined with a conical liner, a new chase locking hoop, and with a locking ring added. This brought the weight up to 125498 lb on 0, with the breech. It also had a 25 cuin on 0-smaller chamber.Friedman 2011 172–173 The Mod 3 guns, Nos. 211–216, were the last new guns built, all other Mods were Mod 0, 2, or 3 guns that were modified. These guns were built with a new simplified design, no liner, five hoops, a locking ring, along with a screw-box liner and a different gas check seat.Friedman 2011 172–173 Mod 4, the twelve guns from Wyoming BB-32 2, relined in 1921–1923, had a conical one-step liner and uniform rifling with a new chase locking hoop and locking ring. With the Mod 5 an attempt was made to reline a Mod 1 with a uniform twist rifling, but it was dropped. Mod 6 relined Mod 2 with a uniform twist rifling along with a modified new chase hoop and locking ring. Mod 7 took the Mod 3 and used a one-step conical liner, uniform twist rifling, and added a tube and liner locking ring. Mod 8 was the Mod 0 or Mod 4 also using a one-step conical liner, uniform twist rifling that was secured by a tube and liner locking ring with a liner locking collar at the breech end. The Mod 8s that used Mod 0 guns also added a new chase hoop and locking ring. Mod 9 was a Mod 2 or Mod 6 that had a new liner with longitudinal clearances at the liner shoulders installed, uniform twist rifling along with a tube and liner locking ring and collar added at the breech end. Mod 10, like the Mod 9, was also a Mod 2 or Mod 6 that had a new liner with longitudinal clearance at the liner shoulders installed, uniform twist rifling along with a tube and liner locking ring and collar added at the breech end. The Mod 10 used Breech Mechanism Mark 9 instead of the Mark 8 on the previous Mods. Mod 11 was a Mod 7 that had the chamber lengthened, adding 235 cuin 0, and a 3½° breech band seating slope and used Breech Mechanism Mark 12. Mod 12 used a Mod 10 and lengthened the chamber and added a 3½° breech band seating slope with Mod 13 being similar but of a Mod 8, Mod 14 used a Mod 9, Mod 15 used a Mod 7, Mod 16 used a Mod 10, Mod 17 used a Mod 8, and Mod 18 a Mod 9. Mod 19, the last modification, used a Mod 2 with its breech modified for the Smith-Asbury Breech Mechanism and the forward end of the chamber modified similar to the Mod 18, lengthened the chamber and added a 3½° breech band seating slope. The breech end was further modified by being machined out so that it could accommodate a gas check seat liner locking ring. The Mod 19 could also be used right or left handed by cutting a new slide keyway that was 180° from the original keyway.Friedman 2011 172–173 Naval Service ShipGun InstalledGun MountWyoming BB-32Mark 7: 12"/50 caliberMark 9: 6 × twin turretsArkansas BB-33Mark 7: 12"/50 caliberMark 9: 6 × twin turretsARA RivadaviaMark 7: 12"/50 caliberMark 9: 6 × twin turretsARA MorenoMark 7: 12"/50 caliberMark 9: 6 × twin turrets Notes 2 References Norman Friedman https://books.google.com/books?id=yh3OAwAAQBAJ Naval Weapons of World War One Seaforth Publishing Norman Friedman 2011 172–173 978-1-84832-100-7 https://www.navweaps.com/Weapons/WNUS_12-50_mk7.php United States of America 12"/50 (30.5 cm) Mark 7 Navweaps 19 July 2016 18 October 2016 Navweaps 2016 https://www.navweaps.com/Weapons/WNUS_12-45_mk5.php United States of America 12"/45 (30.5 cm) Mark 5 and Mark 6 Navweaps 11 April 2016 18 October 2016 Navweaps2 2016 Washington Navy Yard: History of the Naval Gun Factory, 1883-1939 http://www.history.navy.mil/research/library/online-reading-room/title-list-alphabetically/w/washington-navy-yard-history-naval-gun-factory.html Naval History and Heritage Command 30 April 2015 2 June 2016 DANFS 2015 External links Bluejackets Manual, 1917, 4th revision: US Navy 14-inch Mark 1 gun June 2017 Category:Naval guns of the United States Category:305 mm artillery