This might not be in the right section of the forum, so mods please move if necessary.

How come smith still recesses the cylinder of .22lr revolvers, but discontinued the practice on centerfires? Is it cause the rimfire needs more support under the rim to keep the firing pin from esentially crimping the shell into the chamber on firing or what? I have been studying on this and can't figure out why rimfires kept it, but centerfires didn't. Thanks guys.