Main Screw Collar Bearing

Probably a question which has been answered in different ways on here a few times, but I'll ask as it is something I had never thought of until now.

Collar bearing on the action in a MKIII*. I pulled apart this old rifle I got the other day and found that there was indented ring around the screw hole on the action, which I presume is from excessive force on the main screw or a collar that is too long. Now I know a few of the methods to check and adjust collar length to the correct standard, but I never though this kind of thing was possible, or is the ring likely from a lot of shots and the long wearing away from recoil movement?

IN the pictures you can see the action bearing on the fore-end seems pretty good, and the draws are tight enough, triggerguard at first seems to be slightly twisted but I'm not entirely sure just yet.

Let me know what you reckon of the pictures; if it is common and I am just new, or if it is odd.

Cheers.

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