Again. If you mount any sight in place of the rear sight you shouldn't have any problems.
I don't think S&W planned on alot of owners to put many rounds through a 327 having anything attached to the shroud. What happens under recoil , is the weight of an attached optic and heavy metal rail loosens the nut in front of the barrel.
The nut/shroud loosened on me twice! Even after the factory tightened the nut twice. Again. It even happened a third time during and thought I could use the "ewk" tool to tighten . It still got loose.
My 327 has about 10,000 rounds in it now. And I happily shoot it without anything attached to the shroud. Attaching anything to the shroud should be avoided- but by all means. You don't have to believe me.
Picture of revolver when the nut loosened: With the nut loosened, you can unscrew with your fingers to see how it all comes together. If it does come loose, I recommend the factory for tightening. They know how much force to put on an aluminum/ scandium frame without cracking it.
Picture of the tool. I still haven't figured out how to tighten it. And don't want to. It's still under factory warranty. And I don't know how much force they use at the factory. Cracking that frame would be expensive.
This is how I choose to shoot it now. The shroud and nut don't give me problems anymore.
I have posted in most of the 327 R8/ TRR8 threads. A simple search will find them going back a few years. My posts are meant as a warning as what may happen with plenty of rounds with this design, on these Revolvers, putting any weight on the shroud.
Lou