A while back I had one of those Ruger Single Six's with the interchangeable 22LR/22WMR cylinders. The 22WMR shot OK but the 22LR more or less patterned rather then grouped. I suspect that those .222 lead bullets sort of rattled down the .224 bore. I wished that they had instead made the bore .222, but that's just not the "Ruger Way". I suspect that your K22WMR will shoot fine as It is. -S2