Converting it to .22WMR would be my first choice as it's a greatly underrated round that is still far less expensive than centerfire ammo. I had a Model 63 that I loved. One day the apartment maintenance guys came in and walked off with it for some drug hits. They were fired and I never got my guns back. I ended up getting a Rossi M511 revolver that's the "poor man's" Model 63 and it works just as well as my lost 63, is just as accurate as my 63, but it's not my 63. So I'd ream that cylinder for the .22 WMR and go with it. Then if you want a .22LR, find a Rossi made in the 80s.