8 inch gun MK. VI, Mod. 3A2 Principal Characteristics: Overall length of gun: 369 in Length of bore: 45 calibers Number of grooves in barrel: 64 Depth of rifling: .07 in. Length of rifling: 288.79 in. Type of rifling: Right hand, uniform twist, one turn in 25 calibers Type of breechblock: Interrupted Screw Type of firing mechanism: Electrical and percussion Weight of gun with breech mechanism 42,000 lb. Weight of gun and band 55,000 lb Weight of carriage: 103,000 lb Total traverse: 360 degrees Depression, maximum (loading angle) -5 deg Elevation maximum: 45 deg Maximum range (AP 260 lb projectile) 32,980 yds (HE 240 lb projectile) 35,365 yds Maximum service powder pressure 38,000 lb/sq in Muzzle energy (AP 260 lb shell) 15,300 ft-tons Muzzle velocity AP 260 lb, Mk XX (normal charge) 2,100 f/s (super charge) 2,750 f/s fuze: BD Mk X HE 240 lb, M103 (normal charge) 2,250 f/s (super charge) 2,840 f/s fuze: PD M51A1, Model 1 with booster M21A1 Weight of powder charge (normal) 75 lb, 12 oz (super) 108 lb, 8 oz Rate of fire: approximate 2 rds/min Construction of gun: built up Recoil distance: 27 ins mechanism type: hydraulic number of cylinders: 2 Counter recoil mechanism type: pneumatic number of cylinders: 1 Sighting equipment: oncarriage telescope mount M35, telescope M31 References: TM 9-2005, TM 4-210 Catalog of Standard Ordnance Items, Second Edition 1944 Volume II, 15 January 1944 Reprint of TM 4-210 available from CDSG.
|Ramming the projectile, 8-inch gun barbette carriage M1.||Ammunition truck M17 for 8-inch gun barbette carriage M1.|
For the 8 inch Gun, M1, two types of charges are provided for use with the Shell, H.E., M103. One is identified as a M9 (green bag) and the other as M10 (white bag). Both types are of the base and increment type.
The powder in the M9 charge is in the M1 class with an 87-10-3 formula. The grains have seven perforations and a web of .0695 inch. The complete charge weighs 76 pounds.
The powder in the M10 charge is alos in the M1 class with an 87-10-3 formula.
The grains have seven perforations and a web of .1000 inch. The complete charge weighs 106 pounds.
Seperate-loading ammunition, the Mk. XX projectile, is used in the 8 inch, M1888, the M1888MI, M1888MII and Mk. VI, Mod. 3A2, guns. As fired, the projectile weighs 261.8 pounds and contains a bursting charge of 3.4 pounds of explosive "D" which is detonated by the fuze, B.D., Mk. X.
The supercharge (base and increment) of 108 pounds of NH powder is fired by the M30 electric primer. The normal base section weighs 74.251 pounds. The complete round, including supercharge, weighs 369.8 pounds as fired in the Mk. VI, Mod. M3A2, gun.
The base and increment charge used with this projectile in the Mk. VI, Mod. 3A2, gun is 57 inches in length, and 9.25 inches in diameter. The powder in this charge is in the M1 class with an 87-10-3 formula. The grains have seven perforations and a web of 0.1 inch.
The stacked type, two-section propeling charge of NII powder used with this projectile in the M1888 series guns weighs 85.62 pounds. This charge measures 48.5 inches in length, and 8.75 inches in diameter.
The MI class powder used in these charges has an 87-10-3 formula. The grains have seven perforations and a web size of 0.092 inch.
Naval Weapons page on the 8-inch 45 Mk VI weapon
http://www.kadiak.org/artillery/8in.html This page created 2002 September 27, updated 2007 November 15