Former enemies meet again overseas

My dad was a child in London during the war. In the late 1950s he emigrated to Canada to work as a geologist in a gold mine in Northern Ontario. As miners do, they tend to drink and tell stories and my dad overheard one exchange between two very burly old drillers that went something like this:

Franz: So Frank - you were in the war?
Frank: Yeah, Italy.
Franz: Ach so was I!
Frank: I got pretty banged up there.
Franz: I also! What happened?
Frank: Well, we were driving into a little village, we turned the corner and in front of us was a German AT gun. I shot up the crew with the bow MG, but they managed to get a round off and blew our tank all to hell... You?
Franz: I was manning an anti-tank gun in a little Italian village when a Sherman came around the corner and machine-gunned us badly, but we got a round off and took them out....

Dead silence descends on the bar.

Frank: Buy you a drink?
Franz: Sure, the next one's on me.