Well at least you're just dealing with blown primers at this point. I mistakenly assumed all AK47s were 100% reliable and had a M92 SBR'd before I ever took one shot out of it. Shooting it as a pistol didn't really interest me so I just forgot about it til I got my tax stamp. Needless to say, I was a little ticked at myself for not checking that it worked BEFORE I spent the time and $ to have it SBR'd.

***UPDATE***
Problem ammo is ZQI, not Magtech as I originally posted.

Went out today. Adjusted GB, which come to find out it was correct in the first place. Tried shooting 3rds of the ZQI, all had protruding primer anvils. Shot about 50rds of Hornady, Federal, hand loads & Magtech, all w/zero issues. Tried to shoot another 3 rds of the ZQI & all had exposed primer anvils (& smoked out of the front of the BCG unlike any of the other ammo). Shot another 40rds of Magtech w/no issues. It's 100% an ammo issue. Email has been sent to ZQI.

Sending 2 boxes of the ammo I have back to ZQI. They've been helpful thus far & want to inspect/chrono their ammo I have. Their armorer seems to be 99.9% sure it's my gun that's the problem. How can it be my gun when it eats all ammo I put in it except their ammo?

Keep a few unfired rounds for yourself. They want your ammo to remove evidence from your possession and they still want to fault your gun at the same time. As long as they have all of your ammo in question you have no way to prove it was their ammo that was the problem. Of course it don't matter unless you wanted to take legal action against them which at this point seems pointless since there appears to be no damages.

I'm sending them 2 boxes of 20rds each. I'll still have 28 boxes left (bought a case of 640rds)!

***UPDATE***
ZQI shot 2 boxes of my ammo thru their AR10, an M14 & a bolt gun w/zero issues. Sent me video as proof.
https://drive.google.com/file/d/0B3Ohv3iilzdTd0g5a2JpWVVWY1E/view?pref=2&pli=1
Why would my gun shoot all ammo (5 or 6 different loads from 3 or 4 manufacturers) with no signs of over-gassing but when I shoot there ammo I get inverted primer anvils, blown primers & case head swipes? Pleasse enlighten me!

Things to try if you are curious enough

Chrono the ammo


Pull a bullet from one of the problem rounds and use it to determine how much jump to lands.
That would also show you powder weight although that is less helpful as you do not know what powder it is BUT if its a really light charge you can MAYBE assume its a faster burning powder powder and building pressure quicker.

Funny you should say chrono & powder weight. That's 2 things I asked them to provide me but they didn't. I said chrono speeds from the same weapon over 10 rounds & what's the variable? What was the powder weight from multiple rounds? What was the bullet seat depth from multiple rounds? What did the case heads look like? I thought I'd get the answers to these questions & a pic of all the case heads but all I got was "it was all normal".
They say it'd my gun so why does my gun not like this ammo (I'm not talking accuracy, I'm talking gas wise)?

Strange! I guess the good news is your gun seems to like other ammo just fine so you can just avoid the problem ammo. I use to have a single shot 12 gauge that simply would not eject a Winchester shell after it was fired. Had no issues with any other brand or load though.

Sometimes things will just leave you scratching your head. I think in your case if you had tons of time on your hands and plenty of the problem ammo you could probably get to the bottom of it with lots of research, comparing load specs, chrono readings, etc. but if it were me I would just steer clear of that ammo.

I haven't had problems with ZQ! in my M&P 10, but I've read of other people having problems in DPMS. I couldn't begin to assume what the problems might be caused by.

It would probably be safer to just sell of your remaining ZQ! ammo and sticking with loads you know work well.

I guess that's what I'll do. I have 600rds to sell!

good info