Hey Guys, sorry but I'm just reading this now, along with a PM to me from Kevin (who, after speaking with him on the phone last Saturday, is a very cool guy by the way). ;-)
Anyway, hmmmmm . . . . . . (thinking going on in this space). . . . . . I remember something like that happening on just a couple of R9s through the years and it was something minor and an easy fix, even by the owner in the field. Hey Kevin. . . . If you can remove the slide, I'd like to see if you could possibly take a look at the recessed area of the frame where the barrel lug slides back and forth in. We had an issue, for some unforeseen reason, where a burr would build up there from a "stacking of the tolerances" of the barrel / barrel pin / to frame fit and this caused a burr to slow down the action ever so slightly in a manner similar to what you describe here. The fix was very easy. . . . Take a small fine file and remove the burr, which was located in that recessed area of the frame. Simple fix really. With the slide and barrel removed, you have direct access to that area unihbited from the front of the frame and take smooth short strokes to flatten that area out where the barrel rides in. If you can get the slide off and take and post a few photographs, that would even be better. Let me know what you find good Sir. Get back to us when you can. . . . . People waiting to help you here. . . We’ll get that taken care of, "no biggie".
Regards,
Eric R.