Screws loosen because there's motion in the system. The contact between action and its support (Stock, chassis) is incomplete. Somewhere in the system there are high spots and low spots, where they should all bear consistently and don't. Forces are considerable and if there is clearance, there's going to be motion. Overtightening where clearance exists introduces distortion. Messing with the screws is only a band-aid.
Do a rock test. Loosen one screw and check the barrel clearance. Then retighten and do other screw too. If the clearance moves, that shows the action is rocking and that the interface is faulty. There can be no other explanation, and messing with the screws can only temporarily mask the real problem.
The cause can be originating in either the chassis or the action being incompatible with agreed dimension spec, and it could be both. Getting two different makers to agree on who to point the finger at is usually problematic. Small clearances are assumed; all specs have tolerances, and they can stack up.
Failing such agreement, I would try a skim coat bedding solution; but only if the potential warrantee issues can't be resolved. That's because if one initiates gunsmithing solutions before exhausting warrantee options; they void any warrantee. It's a rock and a hard place situation.
My own approach assumes that warranties can be problematic, and I generally find a fix of my own rather than engage in contractual wrangling. But that could also defeat many valuable purposes. I do this because at my age, I could probably die of old age before all of the lawyers get their heads pointed in a single direction. Time is a luxury; and when old, such luxuries evaporate. Assuming responsibility takes on new meaning in old age, and can favor the bolder approach.
I learned this approach from my Eldest Brother. He taught me how to try temporary solutions, like how he bedded Garands with paper mache, doing an end run around Army intramural military match shooting rules.
The paper mache was removable.
Greg
