If any of your spare cylinders are from Ballistix, they already hold 45+ grains of powder with the conical; they're bored deeper than the Ruger factory cylinder. I managed to get 2 Ballistix cylinders for mine as well as the R&D for all round fun. Used cylinders come up for auction from time to time, all mine were previously owned, shoot well and about 1/2 the cost of new.