Re: AR question
load a 30 rnd mag, stand in one spot, aim down the sight, dont look up, shoot all 30 rounds at the target, after your done with your mag, where does your brass land? (spotters help here).
If you have a gas issue due to this "blowout" that you are describing it will show up the most during the cycling of your brass and where your brass pile winds up in the grass.
do this, observe the results, its easily observable