DPMS feeding issue.

[KKing]

[quote name="Dolomite_supafly" post="1094176" timestamp="1389624442"]And what can cause the gun to go from being fine to over gassed? Going from fine to under gassed is pretty easy to do but fine to a point where there is too much gas is pretty hard to do.[/quote] Exactly. If it was a new build/new gun I could see it. But with the low round count there's no way the gas port on the barrel has eroded, just makes more sense for it to be under gassed

[mcordell]

Does your friend or anyone else you know have a AR you could swap the BCG and see how it runs??

That would at least eliminate one thing

[broox]

Does your friend or anyone else you know have a AR you could swap the BCG and see how it runs??

That would at least eliminate one thing

THIS

[RichardR]

And what can cause the gun to go from being fine to over gassed?

Going from fine to under gassed is pretty easy to do but fine to a point where there is too much gas is pretty hard to do.

Normally you'd been correct, undergassing is typically the culprit w/regards to most of the symptoms described, but the OP had also stated that there was also brass being ejected forward.

An AR cannot eject spent brass "forward" (physically impossible) an over-gassed action can & does however forcefully eject rearward & bounce brass forward off the deflector making it appear to be ejecting it forward.

I'd have to actually inspect the rifle before I could accurately diagnose why it went from "fine to over-gassed" without guessing though.

[dcloudy777]

Just because nobody else has mentioned it:  Is the end of the gas tube okay?  It's rare, but they can get struck by the gas key or some foreign object between the gas key and the tube and crimped a little where gas doesn't flow properly.

 

Another tip:  the small  plastic tubing they sell in the aquarium section fits over the end of the gas tube perfectly.  You can use this to blow through the gas tube and out the barrel and check that everything is flowing properly.  This is also an excellent way to properly "clock" a non-pinned gas block. 

[RC3]

Turns out it was a loose gas key. He also replaced one of the springs for something just to be safe.

 

Edit: On the first inspection it seemed fine. It was just loose in such a way, that it was hard to see at first.

Edited January 15, 2014 by RC3

[Dolomite_supafly]

Yeah, I win. I called the gas key in my first post.

 

So what do I win?

[RC3]

Yeah, I win. I called the gas key in my first post.

 

So what do I win?

I would give you a stuffed animal, but I have no idea who you are.

[KKing]

[quote name="Dolomite_supafly" post="1095115" timestamp="1389746334"]Yeah, I win. I called the gas key in my first post. So what do I win?[/quote]

I would give you a stuffed animal, but I have no idea who you are.

I'll be expecting joint custody! ;)

[RC3]

I'll be expecting joint custody! ;)

Oddly enough, I have a long time joke with a friend of mine out join custody of a stuffed lion, to this day, her husband things we are talking about something else.