Buck 881 from the factory with added O'ring on thumb stud

Seen here is the factory Buck ATS34 blade and handle as it came when shipped. I have owned several of these myself and while they are nicely designed folders Buck did seem to drop the ball with the lock contact on them. About every single one I've seen has had blade play. Not all but a surprising number and they came that way. I had to buy three just to get one that locked up solid and I ended up repairing the other two before selling them. Seems they came with the lock contacting the blade such that it allowed what we cutlers call blade rock. Other than this they seemed to be a tank of a folder. It is still worth snagging one if you see it. They are discontinued now by Buck and becoming quite rare.