I don't know for sure if it was a convertable, the barrel markings is .45 caliber, not specified .45 ACP or Colt...Just assumed by that, that it was a convertable model. The ACP round shoots VERY good, with a favorite handload from bags all shots went in one hole at 15 yards, but I have a S&W 25-2 already that is a fine shooters so was hopeing for a .45 colt chambering in the Black Hawk. Any idea on what Ruger would charge to fit a cylinder for it? I need to make a decision on whether to buy or pass.