British Gun, Ordnance QF 6-pounder Mk.II/Mk.IV 1/72 ACE 72563

Ordnance QF 6-pounder was a British 57 mm gun, serving during the Second World War as a primary anti-tank gun of both the British and United States Army (as the 57 mm Gun M1). It was also used as the main armament for a number of armoured fighting vehicles.
The first mass production variant – the Mk II – differed from the pre-production Mk I in having a shorter L/43 barrel, because of the shortage of suitable lathes. The Mk IV was fitted with an L/50 barrel, with muzzle brake.