The Churchill IV combined the 6-pounder gun of the Churchill Mk III with a new cast turret. The Churchill III had been the first version of the Churchill tank to carry a 6-pounder gun, in a new welded turret. However a shortage of suitable weldable sheets of armour plating meant that a new cast turret had to be produced. This had thinner armour than the welded turret of the Mk III, but was at least available for construction. Tanks with the new cast turret were designated as the Mk IV.
Some early Mk IVs were armed with the Mk 5 6-pounder, but most used the Mk 3 6-pounder. The Mk 5 could be indentified by its counterweight, which made up for its longer length.
The Mk IV carried 84 rounds of 6-pounder ammo. It was the most numerous version of the tank, with 1,622 completed. This combined with 675 Mk III to produce a total of 2,297 6-pounder Churchills.
In February 1943 the decision was made to up gun as many older Churchills as possible to take the 75mm gun. During 1943 this was done by fitting the new gun in existing turrets, to produce the Mk VI (more were produced from new). Later on these were given extra appliqué armour, and redesignated as the Mk X LT. In theory there was also an Mk X, which was the Mk VI with appliqué armour and the welded/ cast turret of the Mk VII, but it isn't clear if any of these were actually produced.
Another set of designations was given to Mk IVs that gained the appliqué armour but kept the 6-pounder gun. The Mk IX LT had the original turret and the extra armour, while the Mk IX was meant to gain the welded/ cast turret but keep the 6-pounder gun. Once again it isn't clear if any Mk IXs were actually produced.
Around 700 Churchill Mk IIIs and Mk IVs were converted into Churchill AVREs, an excellent engineer's tank, armed with the short-range but powerful Petard mortar.
50 Mks II and Mk IV were converted into turretless Churchill ARKs.
Churchill Mk IV, A22, Infantry Tank Mk IV
Hull Length: 24ft 5in
Hull Width: 9ft
Height: 10ft 8n
Crew: 5 (commander, gunner, loader, driver, co-driver/ hull gunner)
Engine: 350hp Bedford twin-six
Max Road Speed: 15.5mph
Max Cross-county Speed: 8mph
Road Range: 90 miles radius
Armament: 6-pounder gun and 7.92mm Besa machine gun in turret, 7.92mm Besa machine gun in hull front