Also heard of using Ontos with canister rounds as ambush breakers in convoys. I climbed into one at Camp Lejeune, it was pretty small. Might could almost put two of them on a lowboy.
As far as the M 85s go, they seemed to have a lot of feed trouble. The M2s in the M48s seemed to be more reliable from what I recall. Also, the M85 sights in our turrets seemed to mess up a lot; maybe they weren't saltwater proofed enough.
The setup for the M85 MG in the commander's cupola of an M48A5 or M60 tank was pretty miserable; when we could, we'd sctrounge an M2 off a headquarters compant track or truck, and mount that externally to the *Chrysler gun mount* welded to the outside of the turret. Even an M60 with a 300-round belt was an improvement over the M2HB TTin the cupola, which had only 50 rounds in the spool provided for it, and the cable-operated charging handle of which frequently frayed until it broke through at the worst possible time. Neither could the M85 quick-change barrel be swapped out when cupola mounted, though an experimental setup to use an M85 as a coax was tested for the M48, and that could be changed inside under armor. The 3000-round amnmo belt for it was a considerable improvement as well.