Hello all. New to the forum but not S&W 3rd gen autos. I carried 5906 all through the 90's and for a few years in the 2000's before my P.D. switched to the SW99. Currently own a 5903, 6906, 3913 and recently acquired a slide and barrel for a 4013. The extractor on this slide is wider than than I've seen on other 3rd gen. pistols and was hoping someone can shed some light on it? I have searched, but can find nothing on it so far. Any info or leads about it would be eternal!my appreciated. Thanks.