I think that with solid mounting and Loctite on all screw threads the problem lies with the turret adjustments getting bumped off zero. The reticle gimbal needs to be heavily sprung to stay on zero. Some scopes have double springs for this reason.
BTW, I use 24 inch-pounds of torque on my scope ring screws to be safe. 40 inch-pounds for the Pic. rail bolts.
And if all fasteners are tight and secure it may simply be that you need to go to a very robust scope. (And check zeros when possible.)
->Dare I suggest a Schmidt & "Bendover" PM II? The Marines chose it as their new sniper scope for its "Marine-Proof" durability, among other things. But yeah, it's definitely a home equity loan for that scope.
->Vortex Razors including the AMG have steel gear teeth in their turrets and are pretty tough.
->The Nightforce ATACR is a brute as well.
-> And if you have the $$ for a Leupold Mark 8 I suggest your spend them on the S&B PM II instead.
I backpack using a Kifaru Gun Bearer carrier and have had no zero problems with my SWFA 5 - 15 x 42 scope. But SWFA scopes are known for their ruggedness. You can even use them on powerful air rifles with no problems from the reverse recoil.
Eric B.