The 204 Ruger could be used I think. But with the only one I know that has been done I think they had issues with the extractor /ejector. I believe Stimpylu32 has the gun and I believe Larry Trotter did most of the work. I would contact Stimpy to see if it is still without issues and/or the particulars. If I didn't have an original Remington I would be checking this out myself. Hope this helps and good luck it is a fun rimfire round just wish I could find one of the Taurus revolvers that were said to be made. Kurt