Crimped ammo? 9MM uses a taper crimp. I suspect your "out of battery" experience took place because of bullet set back as the round was forced into the chamber by the recovering bolt.. I am not aware of any factory ammo in 9MM that uses a rolled crimp. The explanation is weak in the extreme. The 9MM headspaces off the case mouth so a roll crimp is not going to work all that well. Would you please weigh your buffer and bolt together for me please.
Sounds like there is a bit of beta testing going on here. Either that or quality control is hit and miss. When we pay over a grand for a rifle it would be nice if they worked flawlessly out of the box. A "friends" Scorpian Carbine works flawlessly OTB as did his Beretta Storm and Ruger PCC, why we have to put up with the drama queens eg my FX9 and apparently, some of the Kodiak K9s is really quite unacceptable but apparently inevitable.
Take Care
Bob
I will try to get weight for you shortly, it's an interesting system that traps the buffer/spring so you have to take off the buffer tube, Not a pin like an AR. The whole bolt rides on 2 lower rods and the bolt carrier thins its diameter to go through a hole in the back of the receiver that is smaller in diameter than a standard AR15, then it contacts a buffer/spring in the tube. Not sure if this is similar to an FX9, I have not handled one.
For my out-of-battery, the case blew at the back. I will attach a couple of quick pictures I had taken that show the blown case and other deformed live rounds.

