Re: R700 sudden loss in accuracy
Regarding that MOA that most out of the box rifles shoot...... most don't.
I take groups of guys shooting frequently, both for work and play. Of the maybe fifty rifles that I have witnessed, all but a handfull needed something fixed to realize their full potential. One particular large gun store chain in Houston is well known amoung our group for it's skill, or more accurately, lack thereof, in optics mounting.
Things that you have already worked thru, wrong mounts, loose mounts, loose bases, base screws too long ( can't close bolt ), WRONG screws, reticle not plumb to reciever, eye relief wrong. All that is in addition to the beating a big bore ( hey, it's Texas, everyone KNOWS you need a big magnum to shoot more than 100 yards) rifle puts on a scope. The names of the broken scopes have not been forgotton. Sooner or later, just about all of them will need repair, but putting 3-400 rounds thru a rifle in a 3-4 day period, tends to bring those things to light quicker.
It is very rare, VERY rare, for any new guy ( or gal, their have been a couple of those ) to show up with a new piece, and have it perform flawlessly for the duration. Most of the issues have been with optics, or the mounts for them. Only occasionally is the rifle itself at fault.
But then, most of the "rifles that shoot MOA" out of the box, don't get 100 rounds in a four year period, much less one day. And most aren't really shooting one MOA either. I love sticking a shoot-n-see up on the target board at the ranch house, exactly 100 yards from the bench. " OK, then you wouldn't mind shooting five at this then?" Before we go out to hunt etc.... most are nowhere close.
There is a reason I keep a gunsmithing toolbox handy!
Seems as if you have learned a bunch yourself getting your new 700 to shoot. If you stay with it, you'll find the learning is a neverending process.