The only .50 gun I've ever seen used on a field was the 3357 I briefly owned a couple years back.
I was shooting Kingman .50 slate through it, which was actually the most brittle paint I've ever seen. The stuff was breaking on green leaves.
Unfortunately, it was also blowing up in the chamber, though whether this was the gun or the paint I can't say.
I ended up selling the gun and the paint.