Hello. Will this sight fit the following models: 327TRR8, M&PR8 and 325TR? I was told it won't fit any of them (screw holes won't line up) but I want to make sure. Thanks.

The bulk of the Extreme Duty rear sights intended for the S&W revolvers will fit the models that you have mentioned

There is no way to answer if the particular one in your hand will or will not fit

What does C&S say?

They say it will fit most N-frames. This morning I verified it will not fit the PC R8, because the screw holes are off. Maybe the TR versions of this revolver will work?

That's a bummer; C&S should know what their product will work with and what it won't.

Another member also found that his C&S sight did not fit his R8. However the sight did fit his M27 Classic and his M29 Classic. So the problem appears to be with the R8, not the sight; apparently the R8 has non-standard sight mounting holes. Question is: why?

Adding to the confusion, I just saw a photo of a TR 325 with the C&S sight installed. No idea if this was a dop-in fit or had to be gunsmithed.

S&W changed the sight hole spacing at some time years ago. You have two choices: drill the frame to match the sight or drill the sight to match the frame.

I'd drill the sight, it's cheaper than the frame.

Agreed.

I think you are referring to 1967 for K-frames, 1993 for N-frames. I could be wrong about that though.

I have been installing that sight on S&W 'K' frames that originally came with the fixed rear sight channel. There I have to drill and tap the frame after milling out a channel for the sight to set in. If I recall correctly, I put one on a 'K' frame that originally had an adjustable sight and while one hole matched, the other hole had to be D&T'ed. I really like this sight. ............ Big Cholla