I performed a detail strip of my USP9 yesterday to clean the inside of the receiver and after reassembling and function checking (every test was flawless), I noticed that if I shook the gun a little, I heard a piece moving a bit... like something was loose. I removed the slide and played a bit more to find out the larger part of the catch was moving a bit (it has about 2mm of play): is this normal ? I noticed something very similar on my USP45 (never disassembled) to a lesser extent. I'm just nervous that I could perform all of the function checks properly and still have something screwed up in there. So, do yours have some play like that or should I be worried??