I recently purchased a replacement 'target' sear for my 22/45 mark III hunter after reading online reviews describing this as as 'drop in' and installation as 'no problem'. Yeah right.
While there is a very good mark III disassembly/assembly guide available here:
http://www.wiztechs.com/knightsrealm...r_assembly.htm
it forgets to mention how to reassemble the stupid magazine disconnect. Grrrr... After about six hour of poking and prodding, searching online, repeat ad nauseum, and probably ruining the micro-finish on my new sear, I finally figured out how to reassemble the magazine disconnect.
The magazine disconnect has a forward facing 'beak' and a rearward facing 'hook'. The trick is how to get everything in its proper place.
Take a good look at the blowout diagram in the Ruger manual. Assemble everything as described in the link provided. The spring goes just to the right (starboard) side of the hammer. The mag disconnect goes next on the pin before it goes through the disconnecter. The beak of this part goes forward.
Assemble the parts, drop into the frame, and insert the pin. The long tail end of the disconnecter spring will be in the magazine well. the front hook-looking part of the spring end up between the sear and the hammer (obviously, this won't work... ) Through the slot in the back of the grip where the mainspring housing goes, you can see a slot in the radial center of the grip. Use a probe to push the tail end of the disconnecter spring through this slot so that it snaps into place in the body of the gun. This may take some fumbling. Then... from the top of the gun, grab the little 'hook' on the front part of the disconnecter spring with a strong pair or tweezers and pull it up and over the front 'beak' part of the disconnecter. There is a small recess here where the spring is supposed to fit.
If anyone can provide more details, or hopefully a more civilized way of doing this, please enlighten us all.