Not sure how accurate this is,but:
"The Wirbelwind design met most of these requirements. Vehicle height was kept low by recessing the gun mount into the top of the hull. The recess allowed for a smaller turret design and kept the overall vehicle height well under the 3 meter limit. Addition of a hydraulic traverse to the turret allowed a traversing speed of 60o/sec. A total of 3200 rounds for the four 2cm guns was carried (with storage for spare barrels provided on the sides of the engine compartment)."
Anybody know what our current traverse speed is?