If you have a continuous rail, low rings will not fit*. I used the mount and it's solid. The large rings appear to work on paper. Don't listen to the internet ninjas.
* Unless you have a dremel and willing to use it. You might have other issues if you're thinking about doing it.
if you can relax and play quordle or nerdle with me it's very interesting. if you don't like it you can change to five nights at freddy's
I had the same issue with medium rings. It touched, though barely, too close for repeated usage.
Well I ordered the medium, hope it works out since I too have a flat rail AR