The pivot and stop pin screws were backing out on my 31 while trying to break it in. The action was still really stiff with the screws fully tightened. Then I noticed that pushing the detent completely off the blade would allow it to move freely, so it definitely wasn't the washers causing excess friction. I bent the lock bar out a little to relieve some of the tension and all the issues I had went away. The action is smooth with the screws tightened down, I can disengage the lock or open the blade without pain, and the screws have not backed out since. Disclaimer: Please be careful if you attempt this. You could potentially damage the knife or make the lockup unsafe. Just wanted to share my experience for those who are having this problem. Whether it was simply breaking in the washers or tweaking the lock bar that seems to have fixed the issue of screws backing out, I am not sure because both things happened about the same time.