Daryl, when I refer to loosening the rear screw I'm not saying it should be loose.

It is, however, fairly routine to torque the front and rear action screws to a somewhat different weight, with the front be dead tight {mostly} and rear, under compression, backed out no more than a quarter turn {usually less}. This with wood stocks that exhibit some springback and allow some amount of continuous compression. I'm not so sure about metal pillars because in my limited experience they are either dead tight or loose, more or less, and both action screws should be turned very tight {other opinions?}.

I'll second Daryl's warning about shooting loosely held together guns; of whatever type {two-piece stocks, one-piece, etc, damage is almost guaranteed.

Our fellow here, it appears, had a situation where at least one, maybe both {??} screws were actually loose due to the indexing.

I never worry about indexing any screw that needs to be tight. I ignore the Mauser locking screws, too, and have some where they are ground out to allow continued tightening or they are just thrown away entirely. The locking screw is, IMO, one of the very few engineering mistakes applied to the total Mauser package. They serve no purpose, proven by the millions of guns that do not sport them. Worthless as a dewclaw on a hound's leg. Only being outdone in worthlessness by the guard screw stock ferrule!