The mags I received with my K100 X-Trim just before the end of 2013 were very stiff the first time I loaded them, and I also had a very hard time getting the 10th round in. I actually loathed the thought of loading another mag, and was looking for a mag loader. A couple of range trips later, and they are loosening up just enough that I'm no longer looking for a loader.
This is my first centrefire pistol, so I'm unsure if this is the norm or not.
As for the range report, I'll leave that to more experienced shooters, again since it's my first centrefire pistol. Also, I shoot at an outdoor range, and temps were minus double digits both times, once after the ice storm we had here (ever shot the ice off steel gongs? - awsome reactive targets!)- so I was basically shooting to satisfy my itch to get out rather than thinking about how well things worked. I can say the gun performed a lot better than I did at those temps.