Here's the factory Accro parts:
Blade, plain black. #51648
Blade, white outline. #54403B
Detent balls (2). #51195
Detent spring. #51683
Elevating screw. #51682
Elevating screw pin. #51649B
Elevating springs (2). #51194
Leaf pin. #95112
Windage screw. #51192B
Windage spring. #51193
NOTE: The same Accro sight was used on ALL adjustable sight-equipped Colt's except for the use of the Ellison sight on the Gold Cup.
The Ellison was a factory option on all guns.
To order parts, check under any Colt using adjustable sights, the parts are all the same no matter what model gun.
These parts are available from Gun Parts, but they use non-factory numbers. Check their web site.
Brownell's carry these parts also, and they seem to use factory numbers preceded by "SP".
You can also get them direct from Colt.
In all likelihood, the rear sight blade is damaged.
On the right side of the blade is a small pointed projection that acts with the windage screw to give the windage screw it's "click".
Sometimes this projection is damaged, and this may be why the screw is in too far.
Id suggest ordering a new sight blade and a new windage screw.
Likely, everything else is OK.
Don't disassemble the elevation screw unless necessary. If you remove the sight from the gun, AS SOON as you get the assembly off the frame, wrap a piece of tape around the leaf and elevation screw to keep the elevation screw pin from falling out.
If it comes out, the elevation screw will come out and it's difficult to reassemble due to the two tiny, TINY balls and spring inside the screw.
To reassembly the tiny, TINY detent balls and spring inside the elevation screw, coat the spring and balls with a thick grease.
This helps keep them in place until you can slip the pin in place.
You can also work inside a large plastic bag to catch those tiny, TINY ^&#@*&% balls.
[This message has been edited by dfariswheel (edited 10-30-2004).]