Free: Contests & Raffles.
I don't own a Glock, but I am a reloader and I've read quite a bit about the issue. What you're referring to is a bulge in the brass. This occurs because a portion of the case (near the head) is unsupported by the Glock chamber. To supposedly increase feeding reliability, Glock (especially) has or once had a long throat leading to the barrel's chamber. The long throat means a tiny bit of the case head area would be less supported than other handgun barrels. When something pressurized to 35,000+++ PSI is unsupported, it's going to bulge or blow out. This is known as a Glock kB. Google images here -> https://www.google.com/search?q=Glock+kB&hl=en&tbo=u&tbm=isch&source=univ&sa=X&ei=I2QQUd_DN8_QigKp0oCgCw&ved=0CDgQsAQ&biw=1366&bih=6642nd generation .40 caliber Glocks are especially known to have this issue. In later generations, Glock has been a little better about chamber support with their barrels, however 100% case head support in a semi-auto pistol is rare, so it's not just a 'Glock issue' (outside of 2nd gen). Glocks just have a higher occurrence of kBs.Replacing the factory barrel with an aftermarket one would likely prevent or decrease bulging of the case, but at the possible expense of complete reliability because the throat geometry would be slightly changed (I really doubt it would make a difference) and the chamber might be a little tighter. Because I reload, and I would want to carry full power loads for self defense or in the field, I would switch to an aftermarket barrel. Better case head support is also going to be easier on expensive 10mm brass.
You can get many, many more than 2 reloads out of brass shot out of a Glock. If someone is saying that, they don't know what they are talking about. Yes, you can get a bulge out of glocked brass mainly .40, not 9/.45, don't know so much about 10mm though. For .40 I use an EGW U die that resizes lower than the typical RCBS Carbide die, for comparison. I would call EGW, Evolution Gun Works and ask them if the .40 die can be used for 10mm (I wouldn't know why not).KB's happen way, way more often from squibs/undercharges and double charges, not because of Glocked brass or OEM barrels and reloads. Yes, you can by an after market Wolf or KKM barrel but that won'necessarilyiy lessen the changes of KB.