The Avenger was a variant of the Challenger with an open turret to help reduce weight, but it never got past the prototype stage. The Avenger was not a complete waste though, as lessons learned from it aided in the design of the Comet cruiser tank. The A34 Cruiser Comet was a British tank that first saw use near the end of World War II. It is often considered the best overall British tank of the war. ...
The GAU-8/A Avenger is a 30 mm, seven-barrel Gatling gun that is mounted on the United States Air Force's A-10 Thunderbolt II.
It is the largest (it is the size and weight of a family sedan), heaviest and most powerful aircraft gun in the United States military (although in a few cases full-sized artillery have been attached to aircraft).
A persistent claim is that the recoil force of the Avenger matches that of the A-10's engines and as such the plane would slow down, stall and subsequently crash if the gun was to be fired for long periods of time.