Object Title

Gun - Ordnance, Breech-Loading, 18-inch Howitzer, Mark I on Railway Proof Sleigh Mark I

Gun - Ordnance, Breech-Loading, 18-inch Howitzer, Mark I on Railway Proof Sleigh Mark I



Object Number



Manufactured during the course of 1918, proofed at Woolwich in 1919 and underwent other firings at Shoeburyness during 1920. Returned to Woolwich after 1921 and then sent back to Shoeburyness and mounted on its current Railway Proof Sleigh in 1940. During the war years it was subject to a variety of test firings inculding those for concrete penetration and indeed thereafter. Footage exists of it being fired in this capacity in 1953 and in 1959 it fired its last round. In 1991 the Minstry of Defence transferred it to the Royal Artillery Historical Trust and it was moved to Repository Road, Woolwich for permanent display. In 2008 it was moved to the Royal Artillery Barracks at Larkhill and then in 2013 to the Dutch National Railway Museum in Utrecht, Holland for a six-month exhibition before arriving at Fort Nelson in September that year on loan.

Physical Description

The howitzer is of steel and consists of two tubes, breech bush, shrunk collar, stop ring, a series of layers of steel wire, numbers I to III rings securing wire, jacket and breech ring. The 'A' tube extends from the breech to the muzzle and is lined with an inner 'A' tube extending from the seat of the obturator and slightly projecting at the muzzle. The inner 'A' tube is slightly tapered throughout its length and secured longitudinally by corresponding shoulders on the 'A' tube and inner 'A' tube over the seat of the obturator and immediately in front of the chamber and the breech bush which is screwed into the interior of the 'A' tube at the rear; the breech bush is also prepared for the reception of the breech screw. The interior of the 'A' tube is prepared with longitudinal grooves from the first shoulder to 8.25 inches from the muzzle to prevent any turning movement of the inner 'A' tube when in position. Over the rear end of the 'A' tube is shrunk the stop ring and shrunk collar. Around the 'A' tube extending over the chamber and a portion of it are wound successive layers of steel wire under high tension and secured with wire securing rings which are shrunk upon the wires exterior. The jacket is shrunk over the exterior of the wire and portion of the 'A' tube and secured longitudinally to corresponding shoulders on the javket and 'A' tube, and the breech ring which is shrunk overbthe shrunk collar and rear end of the jacket and screwed to the latter. Thrust collars are formed in the exterior of the jacket for the attachment of the howitzer to the mounting. The chamber is cylindrical, coned at the front and rear. The breech is closed by a parallel screw having six portions of the screw thread removed longitudinally so as to admit of the breech being closed (when the breech screw is pushed home into the breech opening) by the twelfth of a turn. The gun firing is designed for electric and percussion firing with large vent sealing tubes and is so arranged that the howitzer cannot be fired until the breech screw is fully home and locked in the howitzer.



BarrelBore457.2 mm
BarrelLength17384 mm
BarrelWeight9347 kg


Serial Number S464


457.2 mm

Inscriptions and Marks

12 in B.L. GUN OF 43 TONS TO 16.25 IN B.L. GUN OF 110 TONS W^D R.C.D. 1886 REG No. S.4641 WT 95 TONS.
Sleigh, left hand side
Manufacturer and Date
B.L. 18 HOWR MK.I NO.1 E.O.C. 1918
Breech mechanism
Manufacturer and Date
B.L. 18 INCH HOWR MARK I E.O.C. 1918 No. L/1
Barrel face, breech end


Places Britain


Five of these barrels were scheduled for use during the First World War in 1918 but none were finished before the war ended. Their purpose was to bring more fire power to the Western Front and in particular to undermine the deep defences of the Hindenburg Line. This barrel number L/1 was the first. The Railway Proof Sleigh predates the barrel by thirty-two years. This was used specifically for mounting naval guns of 12 inch 43 tons to the 16.25 inch guns of 11 tons and those in between for their proof firing. In essence therefore they were made to remain on the ranges. This assemblage seems to have been brought together around 1940 at Shoeburyness prior to its use during experimental firings. Prior to this L/1 was proofed in 1919 at Woolwich whereafter it was sent to Shoeburyness for a series of firings including those for Range & Accuracy. It is possible that the wartime experimental firings, some of which involved concrete penetration, were undertaken to assist the work of Barnes Wallis and the manufacture of the Tallboy and Grand Slam air-dropped bombs. Of the other guns, L/2 was mounted on the First World War Railway Truck Mounting 'Boche-Buster' that had seen action with a 14-inch Mark III Naval Gun in 1941 and trained to Bishopsbourne in Kent on the Elham Valley Line to bolster the Kent coast defences. L/3 suffered an accident when being rifled and was lined down to a 16-inch bore. L/4 was similarly mounted on a similar railway mounting 'Scene-Shifter'. L/5 seems to have replaced L/4 on 'scene-Shifter'. All with the exception of L/1 were scrapped in 1945 and afterwards. The detachment numbered 24 and range was 20.3 km (12.6 miles). It was only able therefore to provide extra coast defence for the approaches to the Kent shoreline.