The 9mm is loaded hot compared with 45 ACP, 44 Special, and the wonderful 38 Special. I could not find the old "Speed Kills" videos that I had to watch in driver's education, this modern video just does not have the gruesome, mangled corpses that the old 8mm home projector films had:
When you are dealing with cartridges, the higher the pressure, the faster things go out of whack.
Have you extracted unfired rounds and noticed the cartridge OAL has shortened?
My RIA in 45 ACP, for whatever reason, ejected unfired rounds are shorter. Bullets are being pushed into the case as they are chambered. Recently I had a blown case head, with a 230 FMJ 7.8 grains AA#5, looked exactly like yours. Which chronographs just at 800 fps. That is a bottom end load. The event blew out the magazine base. I was able to clear the pistol, load a different magazine, and keep on shooting. The blast did crack my beautiful double diamond grips. And at the next session, where I absolutely made certain that the ammunition was loaded cautiously, I had a pierced primer with 230 FMJ 7.5 grs AA#5, load retort, and very hard recoil.
I believe my pressure problems are due to the bullet being seated in the case and increasing pressures. That could be your issue.