The post 90 hammer bushing was lengthened when they eliminated the washer. I measured 2 washers; one was .075" thick, the other about .083". The pre 90 hammer bushing is about .57" long and the post about .63". You do not want to mix a post 90 bushing with a washer or you will end up with entirely too much preload on the mainspring. Washers are .375' OD X .263" ID, give or take a little. I'm going to make a few washers in a week or 2 as one of mine sprouted wings and I have not found it.
