Rear sight work for Big Dot replacement on 640

[Cornerpocket]

I recently got a Smith and Wesson 640 and, like a lot of others, am considering changing out the sight. I read a discussion on another website, snubtraining.com, about replacing the factory sight with a Big Dot, which seems to be a popular choice with many. That website advised to "be sure to get the U-shaped rear sight work to go with the Big Dot." What sort of rear sight work are they recommending and does it involve any sort of permanent alteration such that I'm stuck with the Big Dot or some other particular kind of sight, if I don't like the Big Dot? I have a decent idea as to cost for installation of a Big Dot front sight. Any idea as to added cost of the rear sight work? Any other suggestions for a different sight on the 640 would also be appreciated. Thanks.

[BN]

I have a S&W 342 PD with a BigDot. I just float the dot on top of the notch rear sight and get decent accuracy as long as I'm 10 yards or so. I tried a group at 25 yards the other day and had shots off the IDPA target.

[camsdaddy]

I have considered xs for my 60. I would prefer the small dot if I did make the change. I enjoy shooting my snub at 25 yards so I have yet to make the plunge. The snub points well enough out to 7-10 yards I don't know that I'm really aiming anyway.

[Up1911Fan]

Cylinder & Slide mills out a U notch similar the the factory M&P340 to match up with the XS. Looks similar to this.

Attachment 2497

[MGW]

To save a little money and possibly come up with a workable solution try blacking in the rear notch and painting the front sight orange. I saw somewhere that a guy actually took the time to blackout the rear notch with cerakote but a sharpie would be a good place to start.