Just got the MP9. As many have noted the trigger pull is a little "gritty". I don't at this time want to change the pull weight or geometry of the trigger pull at all, only eliminate the gritty feel. After reading the FAQs, I have determined that it is almost certainly caused by rough up / down movement of the firing pin block. With the slide removed, I can feel the same stiction by pushing the FB up and down as when cycling the trigger. Can this be lubed without disassembly? Or do I need to take it apart and polish the the hole and block?