Kyle, is the scope on that rifle proven? Has it been mounted on another rifle and held it's zero? If not, try a second scope and see if your problem persists. Not until the source of the problem has been confined to the scope, mounts or rifle can you find a solution. When you head to the field, choose the appropriate rifle that you have the utmost confidence in. A confident marksman is a deadly marksman; what he's confident with is less important.
As for the flinch thing, if you're not sure, have someone else load the rifle, and when the striker falls on an empty chamber, a flinch will be obvious. If you flinch, you will have to figure out if the flinch is caused by recoil, noise, or the fear of being hit by a scope that is mounted too far to the rear. The .300 is objectionable in both recoil and blast, but recoil can be mitigated with a muzzle break and/or by increasing the weight of the rifle. The sound of the muzzle blast on the other hand, is tough to reduce without diminishing the .300's primary advantage, which is velocity. I assume you wear suitable hearing protection.
If your scope and mounts pass the test, you don't flinch, the action screws of the rifle are tight, and the stock is undamaged, then closely examine your brass to see if it mirrors any misalignment between chamber and bore, or an improperly cut chamber. A pal of mine had a Weatherby that had an improperly cut chamber, glaringly obvious from the shape of the fired brass. Is there any anomaly at the crown such as burrs or a crown that's not square to the bore? Before you go to the trouble of glass bedding, are you going to keep the factory stock on this rifle? If so, bed it. If not wait until your replacement stock arrives, then bed that stock.
Has Loctite changed it's formula? I've used blue Locktite for 30 years without any issue or difficulty in removing screws, I do however use proper fitting screwdrivers, and I've never had to apply heat to get the screws to break loose. Red Locktite on the other hand has messed up more than one gun, but not mine.