Models 66 and 686 Sight Assemblies?

[BuffaloBob]

Asking for Members learned answers to these two questions:

(a) Are the rear sight assemblies on a 4" Model 66/67 -and- a
4" Model 686 interchangeable?

(b) Are the rear sight assemblies on a 4" Model 66/67
interchangeable with the rear sight assemblies on a 2 1/2"
Model 66?

 

[Engine49guy]

The snub 66 sight is definitely not interchangesble because it is much longer at the front of the leaf which extends to the end of the frame so that it mates to the 2.5" barrels front site ramp, ( same with snub Model 15's).

I would have to measure the spacing of the K vs L frame leaf screws but a Model 67, 67-1 or 67-2 site should swap with a Model 19-3, 19-4 or 19-5 site.
The 67-3 and up will have the new rounded site leaf so no.

The 19-2 , 14-2, 15-2 and earlier versions will have a different screw hole spacing because they moved the front mounting hole so it is not right under th Model 19 forcing cone flame blast area, that was the "dash three" improvement.