Here’s the deal with A-MERC. I have quite a collection of the stuff in a wide variety of calibers.
Every single one has an off-center flash hole. EVERY one. Most are far enough off that they were noticeably harder to deprime with my Harvey deprimer. Every maker is going to wind up with flash hole centering problems eventually; that’s caused by tooling wear, and they only let it go for just so long. But if you can’t maintain your production equipment to get the flash hole right
sometimes, what else are you not paying attention to?
The only use I’ve found for this stuff is to make dummy rounds...they size fine, and will hold a bullet fine. But that’s it: dummy rounds.
MaxxTech 9mm cases often have a very pronounced internal step. Here’s a picture I stole from a post on Brian Enos’s Forums:
(Credit: Andy0689, posted August 15, 2016)
That step is probably there to prevent bullet setback, the same way many other makers’ cases have a cannelure rolled into the case. But the step takes up a considerable volume inside the case. Yeah, that means that you’re going to get MUCH higher pressures if you load a “normal” powder charge in those cases. They may be useful for dummy rounds too - probably better than the trash brand because the bullet just cannot set back - but other than recycling ‘em, that’s all the use I can think of for those cases.