The US seemed to stick a .50 on top of almost anything that moved. I wonder if truck drivers, SPG crewmen, tank recovery men, etc, ever received any training or practice on how to use them or if it was on the job training as required. I know they could be fired at ground targets but the mounts were high and designed for AA use. Dad told me that the 6x6 that supported his mortar platoon had one on it and the only time he ever saw it fired was when someone thought they heard something one night and they opened up in that direction. They found an obliterated rabbit in the area the next morning.