Britain 0.50"/62 (12.7 mm) MG Mark III and Japan 12 mm/62 "HI" Type

Britain
0.50"/62 (12.7 mm) Mark III
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Japan 12 mm/62 "HI" Type
Updated 16 June 2012

Vickers started production of this gun in 1926, but service introduction on British ships does not seem to have taken place prior to 1932. This weapon was used on almost all British warships during World War II, many in quad mounts like the ones shown below.

This was a recoil-operated, water-cooled gun with link-belt ammunition feed, and was significantly less powerful than the USN's 0.50" (12.7 mm) Browning M2 BMG. Like the US and most other nations, the British found small-caliber machine guns like these to be ineffective against modern aircraft. Nonetheless, they were still produced in large numbers during the war with an overall total of 12,500 being built.

A few guns were exported to Japan during the late 1930s where they were designated as the 12 mm/62 "HI" Type. These guns were mostly replaced by the start of the Pacific War by the superior 13 mm and 25 mm Hotchkiss guns. An additional 19 guns were purchased by China.

Actual bore length was 62.5 calibers.

Unless otherwise noted, the data below is for British weapons.

0.5"/62 (12.7 mm) quad mount under construction at Vickers
Note the hip rests, used for training this mounting
Photograph copyrighted by The Vickers Photographic Archive catalog number 4952 and used here by courtesy of Lynn Dunning, Development Officer

Quad 0.50" (12.7 mm) on a destroyer
Note that there are both left and right guns

Quad 0.50" (1.27 cm) MG on HMAS Perth
Note the protective canvas covers on the ammunition drums
State Library of Victoria Image H98.105/3191

Single 0.50" (12.7 mm)
Picture taken at HMCS Cornwallis, Halifax, Nova Scotia, Canada, 21 October 1942
SLt H.H. Black / Dept. of National Defence / Library and Archives Canada Photograph PA-106089

Quad 0.5" (12.7 mm) Vickers MG on Mark II* Mounting
Sketch by John Lambert

. Images at The Vickers Photographic Archive

See 0.5 Vickers

Gun Characteristics .

Designation (see Note 1)	0.5"/62 (12.7 mm) Mark III Suffixes No. 1 - For quad mounts No. 2 - For twin mounts No. 3 - For single mounts
Ship Class Used On	Britain: Almost all warships in World War II Japan: N/A
Date Of Design	1926
Date In Service	1926
Gun Weight	56 lbs. [62 lbs. with filled cooling jacket] (25.4 kg [28.1 kg])
Gun Length oa	about 35 in (89 cm)
Bore Length	31.25 in (79.4 cm)
Rifling Length	N/A
Grooves	N/A
Lands	N/A
Twist	N/A
Chamber Volume	N/A
Rate Of Fire (see Note 2)	600 to 700 rounds per minute cyclic 450 rounds per minute cyclic when used with a delay pawl 150 to 200 rounds per minute practical
Notes: 1) The guns for single and twin mounts were similar to those for the quad mounts but had shoulder rests. 2) Each ammunition drum held 200 rounds, which was enough for about twenty seconds of firing. The four ammunition drums on the quad mounting could be replaced within thirty seconds by a well-trained crew.

Ammunition .

Type	Fixed
Weight of Complete Round	2.9 oz (0.08 kg)
Projectile Types and Weights	Bullet - 1.33 oz (37.6 gm)
Bursting Charge	Solid bullet
Projectile Length	N/A
Propellant Charge	2.9 oz (0.08 kg) SC
Muzzle Velocity	2,520 fps (768 mps)
Working Pressure	N/A
Approximate Barrel Life	N/A
Magazine capacity per gun	About 2,500 rounds
Note: Used a 200-round belt carried in a drum. Each loaded drum weighed 60 lbs. (27.2 kg).

Range .

Elevation	With 1.33 oz (0.37 kg) Bullet
Effective Range	800 yards (730 m)
Maximum Range	about 5,000 yards (4,570 m)
Note: Pre-war calculations determined that a ten second burst with a quad mount, equivalent to 500 rounds, could expect 40 rounds to hit a target. However, this analysis assumed that the target area was entirely within the pattern of spread for the duration of the burst, an assumption that meant that both the layer and the trainer needed to perfectly judge the approach speed of the attacking aircraft and then constantly adjust - by hand - their aiming during those ten seconds, regardless of how their ship rolled and pitched during that time.

Mount / Turret Data .

Designation	Single Mountings Mark VI Also some Scarf Ring types Twin Mountings Mark IV Mark V Mark VC Quad Mountings Mark I and Mark I Mark II and Mark II Mark III
Weight	Mark I: 1,605 lbs. (728 kg) Mark I*: 2,200 lbs. (998 kg) Mark II: 2,888 lbs. (1,310 kg) Mark III: 2,580 lbs. (1,170 kg) Mark IV: 1,692 lbs. (772 kg) Mark V: 1,041 lbs. (472 kg) Mark VC: N/A
Elevation	Mark I and Mark I: -10 / +70 Mark II, Mark II and Mark III: -10 / +80 degrees Mark IV: -10 / +70 Mark V and Mark VC: -10 / +70
Elevation Rate	All except Marks V and VC: Manually operated, only Marks V and VC: 50 degrees per second
Train	360 degrees
Train Rate	All except Marks V and VC: Manually operated, only Marks V and VC: 72 degrees per second
Gun recoil	1.25 in (3.2 cm)
Notes: 1) The Mark III mounting had a new type of base plate that was more robust and of larger diameter than the previous types. As opportunity offered, the older Mark I and Mark II mountings were modified to bring them into line with the Mark III. These modified mounts were then designated as Mark I* and Mark II* to distinguish them from unmodified mounts. 2) The Mark VC was an American-produced mounting and could also be used for the US 0.50 in (1.27 cm) Browning M2 MG. 3) Large ships usually had four quad mountings, but HMS Ark Royal had eight. Cruisers had two to four and destroyers had two. The twin Mark IV mounting was used mainly on MLs, MMS, some Bangor class minesweepers, and trawlers. The Mark V twin turret was a light weight unit intended for MTBs but also used on a few LCS(M), destroyers and corvettes. It was hydraulically powered and the belt feed ran through hollow inner trunnions. The hydraulic pump was located off the mounting and this was powered from the engine of the MTB. 4) The quad mounting had its barrels slightly misaligned from each other in order to give a "scatter" effect.

Data from
"Naval Weapons of World War Two" by John Campbell
"Destroyer Weapons of World War 2" by Peter Hodges and Norman Friedman
"Japanese Cruisers of the Pacific War" by Eric Lacroix and Linton Wells II
"British Battleships of World War Two" by Alan Raven and John Roberts
"Anatomy of the Ship: The Battlecruiser Hood" by John Roberts
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Special help by John Lambert and Anthony G. Williams

Page History

07 March 2007 - Benchmark
27 January 2010 - Added picture of single gun
12 February 2012 - Updated to latest template
16 June 2012 - Added picture of HMAS Perth