AR's don't fail by degrees, and the proof is you tube videos?
Nope, that is basically the complete opposite of my position there. I'm not going to belittle you or immediately accuse you of poor reading comprehension like some would here, but here's a better explanation of the statement I made.
The YouTube video the other forum member posted documenting the damage, as well as the photos he posted in the other thread, in addition to his description of the events as they occurred led me to suspect it was not overpressure, and the NEA factory kaboom was just further evidence of it. I think it's reasonable to come to this conclusion based on the evidence at hand, but feel free to provide an alternate explanation based on the evidence we have.
I'm saying that when there is a scenario, be it overpressure or anything else, there is a likely chain of progression of observable damage that usually starts with the weakest link first. There is definitely a range of severity based on the severity of the overpressure.
The problem with comparing what happened two weeks ago to any overpressure scenario is that it doesn't look even remotely similar in terms of the damage.
If you compare two:
The NEA factory kaboom had:
-a severely deformed bolt carrier
-a severely deformed and cracked upper
-a severely deformed lower
-a blown out extractor
-a blown out magazine
-no barrel extension failure
-(unknown if the cam pin or charging handle broke)
The failure two weeks ago had:
-a broken cam pin
-a broken barrel extension
-a broken charging handle latch
-some chipping of the bolt carrier near where the cam pin inserts
-no visible or reported damage to the upper, lower, extractor, or magazine
Let's just assume both events were caused by overpressure for a moment. If the first case had higher pressure and therefore more severe damage, then you would expect to see the damage caused by the lower pressure failure, on top of the damage caused by the higher pressure failure. We don't see this here. You can switch up and assume the second case was a worse overpressure, but you'd expect to see the same effects of the first failure compounded with the second.
You have two documented failures in front of you that share almost no similarities in terms of observable damage. Therefore it's reasonable to conclude that they had different causes. Does that make sense to you?