I've never fired anything above a .308 nothing above that is legal out here. I can tell you that thing makes a nice BOOM, I'd hate to hear a .50 going off.
Oh btw, Gat was a slang term picked up by American soldiers in the vietnam war and has since been adopted through pop culture. It was originally used by British soldiers in the boer war and then by proxy Aussie soldiers.
I'm taking it back.