A word of caution for those using the otherwise, in my opinion, excellent Burris Signature XTR rings.
I have an Alpex sat in a pair of these which enabled my to bring the LRF box in to just above my aiming mark & centrally so I didn’t lose it when increasing the mag.
A few weeks back I took the Alpex off the rifle & popped one of the Diavari 6-24s on it ahead of a Christmas shoot I was going to. The scope had previously been on the rifle & I expected it to be within a ‘knats’ of zero but popped up to the farm to check before the comp as you only have two sighters then 10 to count.
First shot at 100 yards missed an A3 sized target
Brought the target back to 50 yards & next shot clipped the edge of it. Elevation was Bob on though. Made some corrections & all good.
Comp over I popped the Alpex back on & took the opportunity of a range session to check the zero. First shot good for elevation but 450mm to the right

.
Slackened off the mounting screws on both rings & retightened them - next shot 150mm to the right. Better but still not what I expected. Anyway was able to fiddle a bit more & got the correct zero established.
Why was this happening?
I can only assume that it’s because the Signature XTR rings have a clamp on both sides of the ring & as such have no fixed datum that can ensure a mechanically repeatable connection between the ring & the rail.
This has been a lesson well learned for me - now the Alpex has been set back up on the rifle it won’t be getting swapped. I had planned to set up a profile so I could swap it onto another rifle at will but that ain’t going to happen now.
A real pity as part from this I like the rings & their ability to use shims to adjust the alignment of the scope itself & allow the reticle to be zeroed without excessive travel.