robhof
If you want actual Ruger, check with Ruger, if they still have any, they may require your gun to fit. If just functional cylinders; try Classicballistix, they make an aftermarket that is as good or better than the original and about 5gr deeper. The Cb cylinders come with a warning that some fitting may be required, but I have 3 that I acquired one at a time used and from different sources, and they all fit fine and work great.