The late Skeeter Skelton discussed modifying the .45 ACP cylinder of a convertible Colt SAA to use .45 Auto Rim. This was in one of his Q&A columns in Shooting Times magazine. He planned on counterboring the rear of each chamber to contain the rims, as opposed to refacing the entire rear of the cylinder as is being discussed here. He wrote that being able to shoot all three of the major .45 caliber handgun rounds would be "guilding the lily." But then he went on to write that he hadn't gotten around to it and likely never would, as at the time he wrote this (the late 1970's, I believe), .45 Auto Rim ammo was seldom encountered, which at that time was true. He never envisioned the flowering of popularity of .45 ACP revolvers we have seen in the last 20 years, which drove the broad use of the .45 Auto Rim cartridge of today.