16-inch/45-caliber gun explained

16"/45 caliber Mark 1, 5, and 8
Origin:	United States
Type:	Naval gun
Is Ranged:	YES
Is Artillery:	YES
Service:	1921–1947
Used By:	United States Navy
Wars:	World War II
Designer:	Bureau of Ordnance
Design Date:	Mark 1: 1913 Mark 5: 1935
Manufacturer:	U.S. Naval Gun Factory Bethlehem Steel Watervliet Arsenal
Production Date:	1914–1920
Number:	Type Gun (45 cal): 1 (prototype) Mark 1: 40 (Gun Nos. 2–41)
Variants:	Marks 1, 5, and 8
Weight:	230948lb (without breech) 235796lb (with breech)
Length:	61feet
Part Length:	60feet bore (45 calibers)
Cartridge:	AP Mark 3: 2110lb armor-piercing (AP) (Mark 1 gun) AP Mark 5: 2240lb AP (Mark 5 and 8 guns) HC Marks 13 and 14: 1900lb High explosive (HC) (Mark 5 and 8 guns)
Caliber:	16inches
Rate:	1.5 round per minute
Velocity:	AP Mark 3: 2600ft/s AP Mark 5: 2520ft/s Full Charge HC Marks 13 and 14: 2635ft/s Full Charge AP Mark 5: 1935ft/s Reduced Charge HC Marks 13 and 14: 2075ft/s Reduced Charge
Range:	AP Mark 3: 229000NaN0 at 15° elevation AP Mark 5: 230000NaN0 at 15° elevation
Max Range:	AP Mark 3: 343000NaN0 at 30° elevation AP Mark 5: 350000NaN0 at 30° elevation
Elevation:	-4° to +30°
Traverse:	300° max/280° min

The 16"/45 caliber gun (spoken "sixteen-inch-forty-five-caliber") was used for the main batteries of the last class of Standard-type battleships for the United States Navy, the . These guns promised twice the muzzle energy over the Mark 7 12-inch/50 caliber guns of the and a 50% increase over the 14-inch/45 caliber guns of the,, and s.^[1]

Design

The 16-inch gun was a built-up gun constructed in a length of 45 calibers. The Mark 1 had an A tube, jacket, liner, and seven hoops, four locking rings and a screw-box liner. When the gun was designed in August 1913 it was referred to as the "Type Gun (45 Cal.)" as an effort to conceal the gun's true size of 16 inches. Gun No. 1, the prototype, was proof fired in July 1914, less than a year after it was designed. After some minor changes the gun was re-proofed in May 1916 with production approved in January 1917, for Gun Nos. 2–41. Bethlehem Steel was given a contract for 20 guns and an additional 20 castings were ordered from Watervliet Arsenal for assembly at the US Naval Gun Factory at the Washington Navy Yard.^[2]

Upgrade

The Mark 1 guns were upgraded to Marks 5 and 8 in the late 1930s. The Mark 5s have a larger chamber to permit larger charges and a new liner with a heavier taper carbon steel along with a liner locking ring and locking collar. The Mark 8, similar to the Mark 5, had a uniform rifling with a chromium plated bore for increased life.^[3]

Naval service

Ships with 16-inch/45-caliber gun installed

Ship	Gun Installed	Gun Mount
	Guns: 16"/45 caliber	Turrets: 4 × Two-gun turrets
	Guns: 16"/45 caliber	Turrets: 4 × Two-gun turrets
(cancelled 1922)	Guns: 16"/45 caliber	Turrets: 4 × Two-gun turrets
	Guns: 16"/45 caliber	Turrets: 4 × Two-gun turrets

See also

• List of naval guns

Weapons of comparable role, performance and era

• 16-inch/45-caliber Mark 6 gun : successor designed just before WWII
• BL 16 inch Mk I naval gun : British equivalent
• 41 cm/45 3rd Year Type naval gun : Japanese equivalent

External links

• Bluejackets Manual, 1917, 4th revision: US Navy 14-inch Mark 1 gun

Notes and References

1. Web site: United States of America 16"/45 (40.6 cm) Mark 1. Navweaps . 22 April 2015 . 9 June 2016.
2. Book: Naval Weapons of World War One . Seaforth Publishing . Friedman, Norman . 2011 . 157–158 . 978-1-84832-100-7.
3. Web site: United States of America 16"/45 (40.6 cm) Mark 5 and Mark 8 . Navweaps . 4 May 2015 . 9 June 2016.