I found this picture at penlibrary.com, but the mechanism has a solid end, not a flat head screw and my barrel has a slot, not a round hole near the open end. Shows quite well how deeply the barrel screws into the cap (the aluminum-colored piece near the top is threaded), but how does the mechanism come out? And yes, that spring is tapered.
Edited by matt, 21 June 2012 - 03:52 PM.