The brass can bulge in the web area if Unsupported. Not common in 45acp, as the round is low pressure. However, the 40 S&W & 9mm work at much higher pressure.The barrel on the right may have been modified by an Amateur Gunsmith, removing to much metal when polishing the feed ramp. Or it may be just an early model Glock?? If you brass bulges, reduce you load.