100 rounds is not enough to break it in. Metal on metal wear allows parts to fit better, work better. If at 300 rounds, it is still doing it then start to worry.
I would suggest, to start:
-Tear down, Clean and relube
-Try different ammo, say 100 rounds of Wolf, then another 100 rounds of Tiger. Just because one type works poorly does not mean another will do the same.
-Use the other mags, and mark the ones you used today.
