Honestly,,, we all read our brass and primers. Glocked brass. Really does not tell us anything about pressure. Tells me it's a crap chamber if it's bulged. I've seen new retail ammo bought and shot in 9mm, .40 Smith and .45 ACP Glock's and it's came out bulged in this persons pistol and fine in his buddy's pistol. Same retail ammo. Go figure.
I find reading primers gives me more insight than brass. Esp. primers struck with a Glock firing pin.