The bolt resting on the bottom of the stock or rubbing on the sides MIGHT affect accuracy. If it is binding in any way I figure it will cause an issue.
Sorry for the confusion. Yes the forward most scope base screw. It is quite common to have the the screw hit the barrel threads and not tighten the base in front. Only way I know to be certain is to remove rear screw of front base, tighten front base screw to see.
Crowns are hard to see without a borescope. One test that could show a burr would be to run a Q-tip around the crown to see if any fibers are caught on a burr. I used to use the rear ocular of a cheap rifle scope inverted to magnify the crown. The borescope is vastly better. If in doubt recrown.
I think it would be interesting to check everything AND shoot no more than two shots allowing for total cooling to ambient before shooting two more. One test I like to perform on a hunting rifle is to shoot one shot at the target several days apart. After several sessions place all targets together to see the true accuracy. I have a few very trusted rifles that will place that first shot every time into almost the same place making a very tight group and inspiring confidence.
Didn't mention it as it is obvious, don't want to insult, a clean bore is important. What products do you use? Again a bore scope can tell you if it is truly clean. Had a friend at the range come to me and said his accuracy fell off. Discovered he only used hoppes #9 solvent found copper speed bumps in the bore. No kidding the borescope showed lumps here and there. After he used an aggressive copper solvent accuracy returned.
Check out the listed tips, clean up the barrel and retest. Would love to hear what you discover.