The G2 series, and I guess on the G3C (one of my looming G3C pre purchase questions) is that the mag well is a little loose. The little gap between the mag and grip seems to be ubiquitous on this family of weapons. However, a mag with a little tiny bit of wobble isn't bad. Sometimes, slightly lower tolerances help reliability, and I've never had major or even minor magazine issues on the G2 and G3 family of weapons. Occasionally, when sitting down, the mag release will get bumped on my G2 pistols, since I carry 430 concealed. Hasn't happened on my new Bainbridge G2C, and I've gotten into the habit of doing a mag seat check as soon as I get out of a car or whatever, just to ensure it's seated properly. Last thing you want, is when you really need that gun, the mag comes out. Yes, this has also happened on many different handguns just in my own personal experience, even the almighty Glock.
I ordered a 15 round G3 mag from a shop, and it came with the smaller adapter sleeve to fit the G2C and G3C. Pretty cool that they didn't miss that detail. The larger Mecgar mags fit a bit tighter, but it's a non-issue to even my over analytical mind at this point.