I am running multiple sets of those (XTR Sig's) in 34mm and love them (you couldn't give me anything else), but the plastic inserts do tend to cause the ring screws to work loose, and especially during the first hundred rounds or so after mounting.I was looking at the 34mm. ones and I see a lot of bad reports on them any truth to that ? They come with a lot of different inserts but they look different..... jim
You just have to get into the habit of checking them now and then, less often once they have settled in.