First, Thanks for the replies. I've since done a lot more studying, and found some pics of the earlier ones, and can see how much thinner the slides were. I can see why they were prone to cracking, mine is marked 2020 by the safety, and the slide is much thicker. Would that 2020, mean the year of mfg? I feel a lot better about keeping it now, I tried to call EAA today about the availability of upper conversions, but got an answering machine. Does anyone here have any experience with the brass buffer washers, and tapered guide rods? Also I know it depends on the ammo, but is this 10mm with the 3.5" bbl. any better than a.40 S&W?