Removing ignition key barrel
 

just out of curiosity..Is the replacement barrel actually complete on whole assembly?..as it would be easier to just swap out..
Or take switch off column,undo the Top plate by pryin it up evenly with a flat pick or screwdriver..then one small philip's screw at the bottom base.(where the wires are)
Not exactly sure about the Lock mechanism though..Maybe Clokker can chime in on this?

Just the key barrel