Not seen a bullet hole in an exhaust...made a few in bodywork with a 303 rifle...
Not seen any holes in new Mini exhausts but occasionally seen them in the welds on other now exhausts. I think the problem comes from being robot welded.
Its bizarre if I didnt know better I would honestly say its been shot at. Bang in the middle of the silencer no where near any welds or seams a Perfectly round hole. And I know for a fact it wasnt there to begin with.