AR upper issues

[thriller1]

So I found a smoking deal on a couple of 556/.223 uppers from Brownells. I have many AR 15's and this is the first time I've had this trouble with BOTH uppers I just purchased. Both uppers unreliably feed and there is no bolt open on the last shot. I know there is no lower issues because I've swapped out my most reliable lowers. I fully realize you get what you pay for but these things should at least be functional. Ideas?

 

[Bed Wetter]

Carbine, mid, or rifle-length gas system? If I had to guess, it's probably carbine length and over gassed.

 

[thriller1]

You are just the dude I was looking for! Carbine length. $300 lowers with BCG and charging handles with super slim handguards were too good to pass up. What is my fix brother?

 

[2400]

Have you called Brownells? Anytime I've ever had a problem with something from the all I do is call and they either help me fix it or replace or refund whichever I want.

 

[Ericb]

What BCG are you using? With my .300 ive had similar issues using a full auto bcg (heavier). Also what buffer weight are you using?

You could try running it with some hotter amo making sure the bcg is very wet. Some times this will help seel the gas block.

 

[Bed Wetter]

I'm not an AR guru, not by a long shot, but I discovered the internet and there's some useful stuff there. In fact, I haven't had a direct impingement AR for awhile but I just picked one up. All the others are gas piston ARs.

How's it throwing brass? Does the brass go far or not far at all? Does it consistently throw the brass to the same place or does it fly all over?

What sort of jams are you having? Is the next round getting stuck 1/2 way into the chamber? Is the spent brass getting hung up and not ejecting from the action completely?

EricB makes an excellent point. Sometimes you just soak that BCG in oil and let it get good and broken in. You could also take a .30 cal bore brush and spin it through the chamber with a power drill (something I learned from the guys at POF USA.)

 

[jr2280]

May be a gas port issue. Like Bed Wetter asked, I wonder how your brass is ejecting. It should be around 4 o clock usually. Never hurts to call Brownells either. If you got two that function the same odds are others have the same problem.

 

[2400]

May be a gas port issue. Like Bed Wetter asked, I wonder how your brass is ejecting. It should be around 4 o clock usually. Never hurts to call Brownells either. If you got two that function the same odds are others have the same problem.

That was my thinking, may be a run of them with the same problem.

 

[SupressYourself]

It's almost always a gas problem. Documenting where the brass ejects is a good place to start. If you picture the gun barrel pointing at 12 on a clock, anywhere between 3 and 4 o'clock is usually good (assuming they're also kicking out at least a few feet). Putting another ~$100 into each one probably erases the "good deal" factor, but an adjustable gas block can do wonders, and is practically required to shoot suppressed.

 

[Petras]

I'd point towards a gas issue. I actually had this same problem on my AR. I swapped out the 16" dpms barrel for a 20" YHM barrel and immediately began having the same issues (yes I swapped the buffer/spring). What ended up being my problem was the gas port on the new barrel was partially plugged with some of the barrel coating. Got it all cleaned up and she works like a dream now.

 

[thriller1]

First of all, I have to thank all of you for your input. Turns out she was drier than a popcorn fart (the complete upper that is). I took the BCG all apart and oiled it extremely well. My son and I took it out and burned 40 round thru it with no issues. You guys are a class act for pitching in with your experience and making this a lot less painful for my son and I.