While tanks gave the infantry a huge amount of protection, tank armament was also key in their development during the First World War.
The first British tanks carried a formidable array of weaponry into battle. The original production order was for 100 tanks. Their main armament would be two Ordnance Quick Firing 6 pounder Hotchkiss 8cwt guns. This was a Royal Navy weapon adopted as much because it was available as because it was best suited for the role. Secondary armament was to be the Hotchkiss light machine gun.
When the Army increased the order to 150 tanks a problem arose. There now weren’t enough 6 pounders. There wasn’t time to wait for more to be built, so it was decided to fit half the tanks with Vickers heavy machine guns instead, resulting in Male and Female tanks. Another reason for building Females was the fear that gun armed tanks might be overwhelmed by massed infantry attack. Mark Is used on the Somme in 1916 and at Arras in 1917 were armed with these weapons.
The 6 Pounder gun
The 6 pounder had been in use with the Navy since the 1880s and the tank’s designers adopted it because it was small enough to fit in the vehicle, but still offered a good level of firepower. The gun was of 57mm calibre and fired a shell weighing 6 pounds (2.72kg). It could be aimed using a x2 telescope or simple open sights.
The first gunners were trained by the Navy, partly because they had existing knowledge of the weapon, but also because it was believed that the motion of a ship would be similar to that of a tank. In the end firing it accurately on the move proved essentially impossible. The vibration of the tank meant the gunner couldn’t see anything through the telescope, and even if he could, he’d struggle to keep the gun on target.
Mark Is carried 334 rounds, made up of High Explosive and solid shot. Perhaps reflecting lessons learned about its usefulness on the move, the later Mark V reduced this considerably to 207, of which 24 were the new canister shot, intended for use against infantry. The gunner had to squat to the left of the gun and the loader to the right, meaning the two guns had slightly different firing arcs. Their trajectories converged at a point 60 yards in front of the tank.
The Vickers Machine Gun
The Vickers was the British Army’s standard machine gun from 1912.
Female tanks were armed with 4. Chambered in .303 calibre, it had a water filled jacket to cool the barrel, increasing the weight but allowing it to be fired for very long periods. Indeed the Vickers’ reliability soon became legendary.
Female tanks carried 24,320 rounds in 76 boxes, each containing 320 rounds in canvas belts. The gunners sat on a small saddle fixed to the rotating gun mount.
Because of the rapid fire and dispersion of their machine guns, Female tanks generally stood a better chance of hitting their targets than Males, especially if they fired at an area target such as a body of troops.
The lighter Hotchkiss machine gun was the secondary armament of both Male and Female tanks. Males carried 3, one in each sponson behind the 6 pounder and one at the front.
Females had just the front weapon. It fired the same .303 ammunition as the Vickers, but from 30 round metal strips, meaning it had to be reloaded more often.
It was also air cooled, making it lighter but lowering its rate of fire.
The first versions were fitted with a bulky wooden stock, awkward inside a tank. Male tanks carried 6272 rounds.
The 8 man crew also carried personal weapons. These were .455 calibre Webley Mark VI revolvers, far smaller and lighter than the infantry’s rifles.
There were a number of loopholes around the vehicle that the crews could open and fire through at enemy soldiers who couldn’t be reached by any other weapon.
Revolvers were useful, but limited. They held 6 shots, and even the 50 yard range quoted in the training manual was optimistic in combat.
The Mark I’s armament set the pattern for First World War heavy tanks. The Mark IV introduced a shorter barrelled, but functionally identical 6 pounder.
The Mark IV was also fitted with the Lewis gun in place of the Vickers and Hotchkiss, although the Hotchkiss would be reinstated on the Mark Vs and Whippets of 1918.
See more on the Mark IV here.