QF 6 inch /40 naval gun

QF 6 inch 40 calibre naval gun
Type 41 6-inch (152 mm)/40-caliber

Typical naval deck mounting. An early long cartridge case for gunpowder propellant is upended at bottom left, a shell stands next to the cartridge.
Type Naval gun
Coast defence gun
Place of origin United Kingdom
license-produced in Japan
Service history
In service 1892–1945
Used by  Royal Navy
 Imperial Japanese Navy
 Chilean Navy
 Regia Marina
 Argentine Navy
 United States
Wars Russo-Japanese War
World War I
World War II
Production history
Manufacturer Elswick Ordnance Company
Royal Arsenal, Woolwich
Weight 6.6 tons
Barrel length 240 inches (6.096 m) bore

Shell 100 pounds (45 kg) QF, separate cartridge and shell
Calibre 6 inches (152.4 mm)
Elevation -5 / +20 degrees
Traverse +150 / -150 degrees
Rate of fire 5-7 rounds per minute
Muzzle velocity 2,154 feet per second (657 m/s)[1]
820 feet per second (250 m/s) for anti-submarine shells
Effective firing range 10,000 yards (9,140 m) at 20°elevation; 15,000 yards (13,700 m) at 28°elevation

The QF 6 inch 40 calibre naval gun (Quick-Firing) was used by many United Kingdom-built warships around the end of the 19th century and start of the 20th century.

In UK service it was known as the QF 6 inch Mk I, II, III guns.[note 1] As the Type 41 6-inch (152 mm)/40-caliber naval gun it was used for pre-dreadnought battleships and armoured cruisers of the early Imperial Japanese Navy built in UK and in European shipyards.


QF technology

Loading a MK I or II deck gun on HMS Ariadne. The man at left holds a shell, the men at right hold brass powder cartridges. Note the coned breech screw and lugs on the underside of the breech ring to which recoil cylinders are attached

These guns were developed to exploit the new "QF" technology, which involved loading the propellant charge in a brass case with primer in its base. The brass case also sealed the breech, allowing a lighter mechanism. This was presumed to allow a faster rate of fire than the older "Breech Loading" system, where the propellant was loaded in cloth bags and then a separate friction or percussion tube fitted into the breech for firing. The QF principle had proved successful with the much smaller QF 3 pounder Hotchkiss and Nordenfelt QF 3 and 6 pounders from 1885 onwards.

The Mk I was an Elswick gun of built up construction. Mk II was built by Woolwich Arsenal and in 1891 became the first Royal Navy gun using the Armstrong wire-wound construction. The breech mechanisms were developed from the existing 6-inch (150 mm) BL mechanisms, but as it no longer had to provide obturation (sealing of the breech), the front was made coned rather than straight which allowed it to be swung round to the side before it was fully withdrawn, rather than having to be fully withdrawn before swinging to the side as with the BL gun.[2]

Recoil system

MK III gun at Fort Nelson. This shows the left trunnion (detailed in black) by which it is mounted on a Vavasseur recoil slide, and there are no lugs on the underside of the breech ring

The preceding generation of British 6-inch guns (BL Mks III, IV and VI) had old-style trunnions by which they were mounted on Vavasseur inclined slides to absorb recoil. QF Mk I and II dispensed with trunnions and instead on the lower side of the breech ring were lugs to which were attached modern recoil buffer and hydrospring recuperator (runout) cylinders to absorb recoil and return the barrel to loading position after firing. This allowed the gun to recoil directly backwards rather that backwards and upwards as previously, and is the recoil system which in essence is still in use.

Mk III was built by Elswick and was similar to Mk I except that it had trunnions which allowed it to be deployed on the remaining obsolescent but still in service Vavasseur recoil mountings. All 3 Marks had the same dimensions and performance.

UK service

Royal Navy service

The 6 starboard casemate guns on HMS Powerful
Gunnery exercise on HMCS Niobe
A diagram from Brassey's Naval Annual 1896

As the QF 6 inch Mk I, Mk II and Mk III, the gun was used as secondary armament of pre-dreadnoughts of the 1890s and cruisers to 1905. On the armoured cruisers of the Diadem, Powerful and Edgar classes they made up most of the armament, though the latter class carried two 9.2-inch (230 mm) guns as well. The pre-dreadnought battleships of the Royal Sovereign (including the turreted HMS Hood), Centurion, Majestic and Canopus classes carried up to 12 guns.

Second Boer War land service

Gun before use in the Tugela Heights battles of February 1900

During the Second Boer War one gun was brought ashore from HMS Terrible in Natal in February 1900 at the request of General Buller,[3] presumably in response to the failure at Colenso. It was mounted on an improvised field carriage by Captain Percy Scott and transported by rail to Chieveley, just south of Colenso. There it was manned by Royal Navy gunners to provide useful fire support for the British Army during the relief of Ladysmith. It is reported on 17 February to have fired from "Gun Hill" (a small kopje 2 two miles (3 km) north of Chieveley[4]) and knocked out a Boer gun at 16,500 yards (15,100 m), followed by a Boer searchlight, as Buller approached Ladysmith from the South East and pushed the Boers back towards the Tugela river.[5] On 26 February Lieutenant Burne reports firing from the same position on a Boer gun at 15,000 yards (14,000 m) at 28° elevation and falling 200 yards (180 m) short.[6] The 7 ton weight (compared to the 2½ tons of the Boer 155 mm "Long Tom") meant that it was effectively immobile on the battlefield and could not be moved forward to shorten the range.

Two guns were also mounted on armoured trains, crewed by Royal Garrison Artillery men.[7]

Coast defence gun

From 1894 a number of guns were adapted for coast defence use, with the original 3-motion breeches replaced by modern single-motion breeches to increase the rate of fire, which designated them as "B" guns.[8]

Nineteen guns were still active in the defence of the UK as at April 1918 : Jersey (2), Guernsey (2), Alderney (2), Shoeburyness (2), Blyth (2), Clyde Garrison (1), Mersey (2), Berehaven Garrison (Bantry Bay, Ireland) (6).[9]

World War I anti-aircraft gun

Anti-aircraft mounting on Prince of Wales Pier, Dover

At least one gun is known to have been mounted by the Royal Navy on an improvised anti-aircraft mounting on a railway truck, defending docks during the First World War.[10]

Conversion to 8 inch (203 mm) howitzer

In World War I Britain urgently needed heavy artillery on the Western Front, and various obsolete 6-inch naval guns were converted to 8-inch howitzers. Sixty-three QF 6-inch Mk II guns were shortened, bored out to 8 inches (203 mm) and converted to BL type to produce the BL 8-inch howitzer Mk V.[11] Four entered service in December 1915 and 59 followed in 1916.[12]

Japanese naval service

Type 41 6-inch (152 mm)/40 naval gun on Japanese battleship Mikasa

The Type 41 naval gun was designed by Armstrong Whitworth, Elswick, Newcastle upon Tyne, England as a slightly modified version of the Elswick Ordnance Company QF pattern 6-inch (150 mm) guns used on contemporary Royal Navy battleships. It was the standard secondary armament on early Japanese battleships and the main battery on several classes of armoured cruisers.

The gun was officially designated as “Type 41” from the 41st year of the reign of Emperor Meiji on 25 December 1908. It was further re-designated in centimeters on 5 October 1917 as part of the standardization process for the Imperial Japanese Navy converting to the metric system.

The Type 41 6-inch (150 mm) gun fired a 100-pound (45.4 kg) shell with either an armour piercing, high explosive or general purpose warhead. An anti-submarine shell of 113-pound (51.3 kg) was developed and in service from 1943.

US service

Gun relocated from Fort Dade to Fort DeSoto, Florida

These guns were adopted in very limited quantity by the United States Army Coast Artillery Corps as part of the Endicott period fortifications, and were initially mounted 1898–1907. They were acquired in 1898 due to the outbreak of the Spanish–American War. It was feared that the Spanish fleet would bombard US ports, and most of the Endicott forts were still years from completion. So the 6-inch guns, along with 34 4.7-inch Armstrong guns and 21 8-inch M1888 guns on 1870s carriages, were acquired to quickly arm some forts with modern quick-firing guns. They were designated as "6-inch Armstrong guns" and mounted on pedestals in US service, and appear to have been withdrawn from service by 1925. A total of nine guns were mounted in one-, two-, or three-gun batteries, with four of the nine transferred to Hawaii 1913–1917. Eight guns were initially at Fort Williams (Maine) (1), Fort Greble, Rhode Island (1), Fort Wadsworth, Staten Island, NY (2), Fort Moultrie, Charleston, South Carolina (1), Fort Screven, Tybee Island, Georgia (1), and Fort Dade, Tampa Bay, FL (2).[13] The guns at Fort Greble and Fort Moultrie were dismounted in 1903-04. In 1907 three guns were mounted at Fort Adams, Rhode Island, probably the two dismounted guns plus one either newly acquired or from spares. The four guns from Fort Williams and Fort Adams were transferred to Ford Island, Pearl Harbor, Hawaii as Batteries Adair and Boyd beginning in 1913. The two from Fort Dade survive at Fort DeSoto near St. Petersburg, Florida. Their battery at Fort Dade has succumbed to tide action over the years.[14][15][16]

Surviving examples

See also

Weapons of comparable role, performance and era


  1. Mk I, II and III = Marks 1, 2 and 3. Britain used Roman numerals to denote Marks (models) of service ordnance until after the Second World War. This article describes the first three models of Royal Navy 6-inch QF guns.


  1. 2154 ft/second in British service firing 100 lb (45 kg) projectile, using 13 lb 4 oz (6.0 kg) Cordite size 30 propellant, at 60 °F (16 °C). 1,882 ft/s (574 m/s) using 27 lb 12 oz (12.6 kg) gunpowder propellant. From Text Book of Gunnery, 1902.
  2. Hogg & Thurston 1972, Page 140.
  3. Hall, D.D. (1978-06-03). "THE NAVAL GUNS IN NATAL 1899–1902". Military History Journal. The South African Military History Society. 4 (3). ISSN 0026-4016. Retrieved 2009-11-10.
  4. Burne 1902, Chapter II
  5. Bridgland 1998, Page 126-128
  6. Burne 1902 Chapter V
  7. Major D Hall, The South African Military History Society. Military History Journal - Vol 2 No 2 December 1971. "Guns in South Africa 1899–1902 Part III and IV"
  8. Hogg & Thurston 1972, Page 140
  9. Farndale 1988, page 398 - 404
  10. Hogg & Thurston 1972, Page 206.
  11. Mk V howitzer used QF Mk II barrels converted to BL (total of 63). Details from Clarke 2005, page 34, and Tony DiGiulian's website Britain 6"/40 (15.2 cm) QF Marks I, II and III
  12. National Archives MUN5/373/9227
  13. Congressional serial set, 1900, Report of the Commission on the Conduct of the War with Spain, Vol. 7, pp. 3778-3780, Washington: Government Printing Office
  14. Berhow, pp. 92–93
  15. US fort and battery list at the Coast Defense Study Group
  16. FortWiki (Fort Williams, Fort Adams, Fort Wadsworth, Fort Dade, and Fort Screven entries)


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