savage barrel swap

I am going to swap a barrel on a savage 111. There are two questions I have; 1.) Is there a difference between MODELS 110 AND 111 ? 2.) According to the information I have found ther are two thread dia. sizes 1.112 for RUM's and 1.055 for everything else, but I read descriptions "large shank and small shank " for calibers that should all be 1.055. Is this a reference to something else other than the thread dia. ? All of my parts are or (when I purchase them) manufactured in the last ten years. Any info would be a great help thank you.