Not a shootout per se, but I remember back in the 90's taking my S&W 586 up against a fellow with a Browning Hi-Power on a dueling tree.
We went back and forth, hit for hit, 1-2-3-4-5-6, no advantage gained until I ran out of ammo. As I was frantically dumping the empties and trying to reload, he just smiled, took aim and cleaned the tree.
Revolvers are nice, and if the shootout gets over in 6 shots or less then no worry but as I believe I have read here, no one coming out of a gunfight ever wished for a smaller gun or fewer rounds.
