Starline Brass Star45RIMEUP: The .45 Auto Rim has an extra thick rim that allows it to be used without a moon clip in revolvers designed for .45 Auto/moon clip combination. It is built with the same integrity as our 45 Colt case. This case will not work in single action revolvers chambered for .45 Auto(such as the Ruger Blackhawk with .45 Auto cylinder).