I know that manuals say that you can dry fire Ruger rimfires, but I have also seen damage done by doing so...
Not doubting your word, but you could at least give us some kind of hint of what you are talking about. Is there a particular Ruger rimfire REVOLVER that you have seen damaged from dry firing???
If the firing pin strikes the edge of the cylinder there is something wrong with your gun. I have two LCR 22 mag rimfire and neither one allows the firing pin to come in contact with the cylinder.Any 22 rimfire should be fired with snap caps, without them the firing pin strikes the edge of the chamber, it will peen. I have used commercial snaps, some have made their own with fired brass, fill them putty or grout, that will simulate primer in the rim.
If the firing pin strikes the edge of the cylinder there is something wrong with your gun.