From Chuck Hawk's:
"I hope your self-defense .45 Colt is a good double-action design like the Smith & Wesson Model 25 and not some single-action hunting gun. Load your revolver with the Cor-Bon 200 grain JHP. The Federal 225 grain Lead Semi-Wadcutter Hollowpoint (C45LCA) or Winchester 225 grain Silvertip JHP (X45CSHP2) are also good." LINK
If I had a shotshell handgun, I'd also use 45 Long Colt instead of shotshells. OTOH, you've got 2 big challenges: 1. Availability of ammo. 2. Does your Governor ACCURATELY shoot conventional handgun rounds? As bapple mentioned in a different thread, the majority of Governors and Judges aren't very accurate w/ conventional loads. If you haven't alerady done it, I'd shoot some 45 Long Colt rounds in your gun and see how accurate it is.