It appears this could be an RSA problem. There is an inherent problem with the guide plate bending, and if I did not install it "deep" enough last time I stripped it, the plate could be bent and could have pushed up in the way of the slide when trying to take it off. Looks like it will have to go back to S&W. Not happy, to say the least. Glad I have another EDC. Thanks again to everyone for the help.