I think a 50 cal round would tend to do some damage. My understanding is that the 50 cal was used to disable SCUD-like missiles - a sniper would get close to the launch truck, and put a round through where the electronics were.
My other post should have had a "sarcasm" tag on the end of it - maybe you recall the threads here on FR where Nostrils Waxman claimed that 50 cal rounds could be used against tanks, etc.