Yet another thread about this, but the mods and how-to's I've read have left me with a pen that has either crappy click action or a sloppy fitting nib that has side to side play that can be felt while writing so today I set out to figure out what I could do to improve it. For this thread I'll assume you already know about this mod, otherwise this may not make a lot of sense. The first problem seems to stem around the little white/clear insert in the tip of the pen that the refill moves through when clicking. The hole is just a teeny bit too small for the Fisher cartridge to move through without hanging up. I've seen suggestions from trimming down the tip of this insert to removing it altogether, both of which created slop in the nib while writing which is just unacceptable. My solution is to use a tapered diamond sharpening rod (mine is a cheap Smith's that I got at Wally World) chucked into a drill to sand out and open up the hole just enough to allow the Fisher cartridge to move through here smoothly without hanging up. The goal here is to open it up just enough that the spring can overcome the friction from the cartridge moving through the hole. I've even gone so far as to try lubing the hole a bit, and a teeny bit of Vaseline does wonders here. I tried it like this, but I suspect the insert is spinning inside the tip.. So you may need to try it like this, which is a bit harder to hold onto but it got the job done. This can be a little tricky because the insert is almost rubber like and will stretch easily, but once you put it back into the pen tip it returns to it's normal size so it definitely needs some sanding inside to open it up a little. Part 2 So that was half the problem. After that I had a pen where the Fisher cartridge moved through the tip nicely, and fit snugly so I couldn't feel any slop in the nib while writing. However, the clicky action was screwed up somehow. It would click in and out and seemed normal until you started to write, when you would feel this initial "bump" when you first pressed the pen down, where the cartridge was moving/seating itself further up inside the pen, and that drove me CRAZY. After this initial bump, it wrote fine and there was no slop, but that initial bump feeling really sucked and would tend to screw up the first bit of writing you'd do. I fiddled around with swapping the clicky mechanisms around from the 701 to the 402 mechanisms but it didn't seem that either made a difference (and in the end I'm actually using the 402 mechanism but they seem idential). I came upon the solution by accident... This little spring in the clicky mechanism/under the plunger seems to be the culprit. Leave this little turd OUT. It doesn't actually seem to have a function. I've tried writing and clicking the pen with and without this stupid spring, and it seems that little bump action at the nib is somehow related to this spring, because with it removed the action is perfect and doesn't have that initial bump when pressing the pen down to write. The spring at the tip of the cartridge seems plenty strong enough to work the clicky action so I'm not sure what the purpose of the spring is but it causes problems with this mod. Now I've finally got the $5-ghetto-tactical-write-anywhere pen of my dreams lol.