The ATI came loose on me !...never tried it with locktite tho.
I bought a No5 with an S&K mount , I don't know how much it was shot prior to my ownership but I've burned well over 200rd with no issues. Even with that little extra recoil the No5 has , the S&K has worked out very well.
The B-Square holds well too and I will shoot with confidence using it. The trick with the B-Square is to make sure that it has a solid contact where the rearsight pin goes through and replace the rearsight pin that comes with the mount , with a bolt/nut.
A Mk11 300/600 sight can also still be used with the B-Square
The ATI , S&K and the B-Square mounts all sit about the same height over the receiver and you might want a cheekpiece.
There are the traditional wood pieces that screw onto the butt , if you have trouble locating one , the leather Garand cheekpiece , turned and trained to sit high on the butt's comb works reasonably well too ....no real need for screws , looks good and is quite comfortable.
...works on a SKS as well
Winchester PowerPoint CXP3 -180gr , is a good moose load out of my rifle but that might change ( accuracy ) with a different rifle(s) and barrel wear.
Practice up , play'er safe and have a good time !