I just got done adjusting the creep in my M77 7mm Rem Mag and when I put it back together I cranked down the the rear bolt/screw (just in front of the top tang safety) and the tip of the bolt/screw (sticking up) interfered with the movement of the bolt action. I seem to remember running into this this last time I took the action out, which has been a while. My remedy then was to to back the bolt/screw off a little to give the action bolt free clearance. Now I'm wondering if that might have anything to do with the deteriorated accuracy of the rifle?
I see two solutions...First, grind down the tip of the bolt screw to shorten it...or...Second, put a locking washer in to take up space. If I grind down the bolt, it might be a real hassel to get it to thread again. Anything wrong with using a locking washer?