jimmyjames8 said:
bulged brass can be cured with an appropriate non chamfered die or a small base die and proper die and press set up.
I only quoted a part of your response, but know you went on to say that there were still problems with the .40 rounds in Glocks. The following summary may explain part of the issue.
Bulged brass can be reformed, and it will look right, but folks who are familiar with the nature of brass have told us on other forums that some bulged brass is changed brass, and the bulged area, when reformed, can be very different.
Metal that has not been pushed past it's elastic limit (also called its "yield point") will return to something like its starting position or shape, and will be as strong as before. The steel in a gun frame or a spring will give but return to its original position or shape on its own because its internal structure is undamaged.
Brass is more ductible, more easily changed, and brass that has been pushed past it's yield point -- as might be the case with brass in a Glock chamber that doesn't support the case fully -- will suffer metal fatigue and undergo all sorts of internal changes, such as very small micro-fractures. After a big bulge, the brass is often permanently changed and is no longer as strong or resilient as before. It may look the same, but it isn't.
Depending on where the reshaped area in the brass is positioned when a once-bulged but reloaded round is chambered, that "reformed" area of the case may be properly supported, or NOT. If the previously bulged area is positioned over an unsupported spot in the chamber, things can get ugly -- as that area is very weak. That may explain some of the .40 issues in Glocks, if the shooters involved loaded their own and also had the older barrels with unsupported areas in the chambers.
It's my understanding that most Glock barrels, since about 15 years ago, offer better case support -- as do nearly all of the after-market barrels available.