The turret was carved from insulation foam. The gun barrels are 1/72 aircraft undercart legs. The same rummage in the spares box yielded the radar dish - the base of a stand for a 1/144 scale aircraft model.
Shilka with a T-55 - it looks about the right relative size.
Dodgy Shilka with dodgy Sgt. Yuk. A ghastly duo!