I just received my CS40 recently. I am having difficulty placing that last 7th round into the magazine. This issue goes for both magazines. The gun is basically new having been fired a few hundred rounds.
When compared to the CS45 that I also own, it appears as if the magazine construction is somewhat different, particularly with respect to the follower. On the CS45 the seating of the follower has a tighter fit when compared to the CS40.
Also I am curious as to the color coding of the magazine follower: the CS45 Black & CS40 White. Perhaps this was to distinguish between the calibers.
Your input is greatly appreciated.