As fitted to the Charioteer, it ran through two models: The L7 105 mm tank gun was developed from the 20 pounder.

[2] The gun was fitted predominantly to the Centurion tank, first seeing action in 1950 with British Army units during the Korean War and Suez Crisis (1956).

[4]) Between 1968 and 1971, Mk 5/1 Centurions of the Australian Army, equipped with the original 20 pounder, saw action during the Vietnam War.

In the context of counterinsurgency operations in South Vietnam, the 84 mm ammunition of the 20 pounder was considered suitable for the armoured fire support role.

The 20 pounder's APCBC projectile had an initial muzzle velocity of 1,020 metres per second and could penetrate 210 mm (8.3 in) of rolled homogeneous armour (RHA).