This R&D conversion is for the Ruger Old Army. The RDROAC converts your Ruger Old Army style revolver to fire the venerable .45 Colt or .45 Schofield Cowboy cartridges! The cylinder was engineered to have a six shot capacity, and to be able to use it in CAS competition, The RDROAC was examined and approved for SASS use by the Territorial Governors. The RDROAC is to be used with either smokeless Cowboy loads or Black Powder 45 Colt/Schofield ammunition. Please see our large selection of cowboy ammunition.