I have had my C9 for about a year now and have had virtually NO problems with it. I purchased a Set of THOMAS (Spalted Maple) grips and installed them and had difficulty with the Magazine release... reinstalled ORIGINAL grips and now when I LOCK the slide Back ... and then use the RELEASE button, the slide does NOT go forward. I have to drop the Magazine and MANUALLY move the slide forward. When firing, NO FF's, NO FE's, BUT the slide does NOT lock open on LAST round fired... it DOES eject it just does NOT lock open. ANY IDEAS? I did a CURSORY Barrel clean (Patch down barrel) ONLY... I did NOT take the gun down. I am reluctant to send it back for something so simple. Thought I'd run it by Y'all first. What say you???