Well, I also have a cowboy revolver in .22 cal which has swappable cylinders to accomodate both 22LR and 22WMR, however, LR is .221 and WMR is .224. It is generally known that the performance of the 22LR in these guns suffers. Thats OK for a plinker, but if I am going to get the big .357 / 9mm, I want to know that both rounds are the same size, and thus will shoot accurately through the same barrel.
Thanks