This is a great design but quality control on the washer was lacking. When the washer is installed it should not be a press fit in the club head. This compromises the locking function of the washer and does not let it lock the assembly when tightened. A lock washer that is smashed flat and held that way by anything but the screw assembly is nothing more than a flat washer. No wonder there are so many complaints about these things coming apart during use. I ground about .020" off the O.D. of the washer and it worked perfectly. The washer should easily fall to the bottom of the club head pocket with no restriction. Hireko should fix this problem and supply correct size washers. For those that can do it yourself, it's a fix that only takes a few minutes.
Fix this problem Hireko and you have a winner.