Be sure that you watch which ring is which, there is a front and back ring and different length screws. Also don't over tighten, Browning does not give out torque specs. The threads are a bit shallow. I used loctite and snugged them down, no issues.
Two quick things: not all of them come with different screw lengths - I remember hearing a while back that this was the case, but the rings I just bought had screws all of the same length. The taller part of the base was just countersunk.
As for the base screw torque settings, I emailed Talley yesterday to check, as the ring packet doesn't give a figure; both it and their website say to contact them for the right amount.
I'd seen a few posts online suggesting 18 in lbs for the rings/tops, and 25 for the ring base screws. Talley said only 18 in lbs for both. I wrote back to double-check whether they hadn't meant 25 for the ring base screws - their reply was "Not on an Xbolt. There are only 2 threads in the gun on the front 2 screws."
So there we go - 18 in lbs for both the rings and the ring base / action screws.