Ahhh, the famous Glock Belly. Some cases fired in the earlier Glock barrels had a tendency to bulge excessively in the less supported feed ramp area. Those I full length resized worked fine. It's easy to overwork the brass in the area of the bulge resulting in a blown case head, so check your brass carefully. Actually, it's easy to see the bulge with the naked eye, you might be ahead of the game by chunking those. My .40 S&W reloads are on the moderate side, and I have not had any problems with using the cases after proper resizing. It's rare these days finding fired brass with this bulge. Check your rounds with a chamber gauge after reloading to insure they chamber, keep your loads on the mild to moderate side and all is well.
Savage