I torqued my Spuhr to their spec with fix-it-sticks and I had only shot it a few times before I noticed cracking on mounting piece that holds it on. They replaced it but I'm the type of guy that when something fails on a product and has happened to mulitple people, I'm done. You shouldn't be testing your gear on the public, but instead during development, and then do batch testing from time to time. I bought the Nightforce mounts used on the MK22. People they were picked because they were low bid but I've never heard issues of them cracking or losing zero.
The Nightforce is a good option too. Just something to be aware of; The repeated slamming closed of the receiver MIGHT be causing a shift in zero.
We have to open the receiver and remove the bolt after every serial/range trip for safety.
The receiver is opened, bolt removed, rifle cleared, receiver closed, move to new FP, open receiver, insert bolt, close receiver, load.
We've asked about and though no one has directly stated it has happened to them, or that they are willing to blame a POI shift on the optic shifting, by all logic, if you're too rough closing the receiver it COULD cause the mechanics of the optic to move.
We have a MARK 5 HD on the MRAD in the C1 Mounts.
I ran the MRAD in a competition and about 3/4 the way through I had a POI shift .3 high and about .4 left.
Could've been the heat and just being shit that made me change my firing position and cause the shift, but when we tested it on paper, it had definitely shifted. Process of elimination would suggest that, if all torque is good, ammo hasn't changed, then it's got to be the optic itself.
Admittedly, i'm just propping it up and letting the upper receiver fall under it's own weight and slam closed, so it's probably my fault anyhow.