Quoting myself here for an update. I am about 300 rounds into a 1300 round 40S&W session. Out of the first 300, I have found 26 that will not chamber due to the "Glock Bulge". Some are so bad that they look like they have a magnum belt around the bottom!
So, I will pull those and run them through a Redding GRx die once it arrives along with the rest of my 40S&W cases. 26 failed rounds per 300 is just too high of a failure rate. I can't afford to have one or more not chamber during a match or God forbid a defensive situation.
I have heard that Glock 40 barrels have more of a lowered (unsupported chamber) feed ramp than others to ensure reliability for military and law enforcement. I can tell you for sure that I only had 3 out of 1000 rounds of 9mm that did not pass the chamber check. All of it was range brass too.
I have two Glock pistols and both barrels have been replaced with Bar-Sto Precision barrels. They are fully supported and fairly tight. No way they are going to eat this bulged brass. Hopefully, the GRx will do the trick.
Here is a picture of my 40S&W belted magnum loads: