In June 2015 Ruger announced a production Redhawk version that supports both the rimmed .45 Colt round and the rimless .45 ACP round., Ruger achieves this multi-cartridge functionality by partially machining the cylinder for use of moon clips for the .45 ACP while still retaining enough ledge on the cylinder to allow proper .45 Colt headspacing., For several years gunsmiths have been customizing DA/SA revolver cylinders (manufactured using modern metallurgy) of .45 Colt, .454 Casull or .460 S&W Magnum chamberings to accept .45 ACP (and possibly other calibers) with moon clips in addition to the revolver's original round(s). However, Ruger's .45 ACP/.45 Colt Redhawk offering is one of the first factory-produced, manufacturer-standard revolver models with such a machined cylinder.