Mine does this too, and when I got it I asked around, everyone's pretty much does this. The spring in the mag is probably just not softened up. Fill the mag, pop it in, and don't rack a round. Let it sit like this, the mag's spring will soften and it will be easier to pop the mag in.
Also had the same issue when I first got my G30, it's a very stiff spring, and I loaded 9 rounds in it for a bit till the spring softened enough to accept a full 10 rounds in my mags, seems to be a common issue as I have heard this in other forums and with my friends also, nothing to worry about though