I have two mags that came with my G30sf, plus I bought three more new from Glock Team. I noticed that only two of the five could take 10 rounds. One of my original mags (they are all new, I just bought the gun) can take 10, but rattles when fully loaded. The other generally could not take 10, but when I managed to cram 10 in, it acted like an old non drop free mag - very hard to insert into the grip (not talking about locking it in, I mean it was like bulged). Anyway, I took apart all 5 mags. Inside each, there was an extra dab of plastic from the metal/plastic bonding. I used the blade from a Swiss Army knife to shave those off. One was on the front below the .45, the other opposite that on the back of the mag. They should not have interfered with the follower, but under recoil, who knows. Next I worked each spring by hand. Expanded and compressed. Made sure to compress the small loops fully, and square on top of each other. Spent about 10 minutes on each working the springs. You can't break them, and if you pull them too far apart they seem to be easy to get back into place. Put them all back together and BINGO. All 5 mags now take 9 rounds by easy finger loading, and the tenth goes in with the Glock tool with no problem. The first time at the range I got a couple of ninth round FTF with WWB JHP. I always suspect a mag problem, so I will be off to the range this week to test out the mags now, but I have a feeling this is the cure. The springs can't compress enough inside the mag to get down to where they need to be since the follower and spring itself gets in the way. Doing it by hand seems to cure the inability to load #10 - in fact, in two of the mags it was impossible to load 10 no matter what I did, now they go in without that much effort.