1) Remove spring pin

2) Remove limiting ring

3) Unscrew elevation correction screw as far as the stop

4) Unscrew windage correction screw

5) Push in click stud for windage correction screw using a punch and push rear sight drum forward

6) Slip out rear sight drup upward and simultaneaously hold fast click stud for windage correction screw by hand

7) Remove click stud and compression spring

8) Unscrew insert

9) Remove safety washer for rear sight drum using a screwdriver

10) Remove leaf spring

11) Seperate rear sight drum from pivot

12) Remove drum stud and drum spring

13) Unscrew Elevation correction screw

14) Push Drum axl, spring washer and rubber disk out of rear sight drum
 
 
 
 
 
 
 

1) Put Washer into the rear sight drum, the curvature pointed downward

2) Put drum axle on the spring washer

3) Squeeze rubber disc into the rear sight drum

4) Screw insert into the rear sight drum

5) Insert drum spring and drum stud into the bore

6) Screw elevation correction screw entirely into the pivot

7) Put together pivot and rear sight drum

8) Put leaf spring on the drum axle

9) Mount safety washer

10) Put rear sight spring into the bore

11) Put pivot from above into the rear sight mount, the click 
stud's bore being visible in the hole of the windage correction screw

12) Put click stud on the compression spring, through the bore of the windage correction screw

13) Push click stud inside, using a punch and simultaneously punch pivot with rear sight drum downward

14) Screw in windage correction screw

15) Mount limiting ring

16) Insert spring pin

17) Turn elevation and windage correction screw until the rear sight stands in the center.

2.    When you lift out the drum sight, be VERY careful as the windage adjustment is under VERY strong spring tension.  You don't want the small parts to shoot out across the room (or into your eye)!  I would put a heavy-ish cloth over the whole rear sight before you lift it out - and put something soft beneath for when the parts drops on the floor.