Try to find .22LR ammunition that doesn't have lead bullets. If you do find it, don't shoot it through a gun, as the barrels aren't hard enough steel for copper.
Seems to me most 22LR is copper jacketed. And are you saying that 22s use softer steel than other guns? I've never heard that. Not that it has anything to do with my original post.
My guess is that all the big manufacturers will start putting out non lead rounds in most cartridges including 22LR.