The A30 Challenger is one of the less common Cruiser tanks since it quickly was made obsolete by the A34 Comet that became the wanted 17-pounder complement to the lighter armed Cromwell Cruiser tanks. It shares the turret design with TOG-2, though it is much more mobile just like the other Cruiser tanks.
Curiously, the Challenger, TOG-2 and 3 are the few British tank designs with a coaxial M1919A4 Browning. It's rate of fire is slightly higher than that of the common Besa Mk.I, but the Mk.III in advanced vehicles like the Centurion Mk. IV is higher.