BL 12-inch howitzer

Following the success of their BL 9.2-inch howitzer, Vickers designed an almost identical version scaled up to a calibre of 12 inches, the Mk II entering service on the Western Front in August 1916. Eight complete equipments are reported as arriving in August 1916 and being in action in France shortly afterwards. It was similar but unrelated to the BL 12-inch railway howitzers Mk I, III and V produced by the Elswick Ordnance Company at the same time. The Mk IV was a more powerful version with longer barrel produced from 1917.

As with other large-calibre weapons, it was operated by the Royal Garrison Artillery in World War I. The 12-inch was dismantled and transported in six loads mounted on traction engine wheels, and drawn by traction engines or Holt 75 caterpillar tractors, explaining why troops called it the “12-inch Road Hog”. It was then reassembled on its static siege mounting on top of a steel holdfast, with 22 tons of earth in a box sitting on the front of the holdfast in front of the gun, to counteract the kick of firing. Guns still remaining in World War II were deployed in 1940 for British home defence in anti-invasion positions. In 1943, a “Siege Train” was proposed and an anti-concrete shell designed. The idea was dropped and the shells never produced. The 12 inch Howitzer was declared obsolete in March 1945.

On October 8, 1914, the Main Artillery Directorate (GAU) signed a contract with Vickers (Deadline of July 1915) for the supply of four 305 mm siege howitzers (310,000 rubles for each howitzer) and 3,200 HE shells (640 rubles each). At the same time, 143 tractors were ordered from England to transport 305 mm and 203 mm howitzers. On December 2, 1914, a new order was placed for 5 howitzers (Deadline of October 1915), and 4,000 HE shells. The total cost of the second order is £147,000. In 1915, 2 howitzers arrived in Russia from England, and the remaining 7 arriving in 1916. By the spring of 1917, 8 howitzers were included in one battalion of the 202nd Artillery Brigade, forming 4 batteries with the letter "D". The subsequent fate of these howitzers could not be determined. By 1922, the Red Army or warehouses did not have complete 305-mm Vickers howitzers. In May 1922, three carriages from these howitzers were sent to the Tambov artillery depot. The shells from the howitzers were included in the ammunition load of the 305 mm howitzer Model 1915.

Gun variant: Mk II – Bore of 13.3 calibres Mk IV – Bore of 17.3 calibres Carriage variant: Carriage, Siege, Mk I – Similar to the siege carriage of the 9.2-inch howitzer. Designed to be used with the Mk II gun. Carriage, Siege, Mk II – The addition of a hydraulic rammer. Designed to be used with the Mk IV gun.

305 mm howitzer M1915 — Russian equivalent (and could use the Vickers ammo) Skoda 305 mm Model 1911 — Austro-Hungarian equivalent