Ron Don, you are correct. According to the Worth cataolgue, 00 colorado blades measure .440" (less than 1/2"). 00 indiana blades measure.434" (smaller yet). 0 is smallest willow leaf they offer at .568". Hope that helps all who are looking. Butt rings, are those the single wire loops? I've not used them and was wondering the reasons for doing so. I have split rings so I use them, but that supply is withering.