Failure to eject??

[MUNCHIE]

I just assembled the lower this afternoon and put the uppe,r which I bought complete with bolt, on the lower and took it out for the first time this evening. This thing jammed on the second round and would not eject, the brass came out really dirty as well. I swapped the bolt assembly with a different gun and it worked flawlessly but the weird part is that my bolt worked just fine in his gun. Same ammo, same barrel, I have a midlength and his is carbine. Can someone help me out here, the only thing I can think of is that the bolt may be a little tight but I could not get my buddy to swap me...

[NYY]

put up some pics. would help a ton

[evidens83]

What kind of ammo?
Which BCG?
Which magazine?

[dieselpower]

Inspect your bolt. Whats your buffer/spring combo.

[Vanilla Gorilla]

is there a difference in the bolt carrier? like one is a auto bcg and the other is a semi bcg?

[MUNCHIE]

put up some pics. would help a ton

I am not sure what you want me to take pictures of? Everything is brand new with no defects that I can see

What kind of ammo?
Which BCG?
Which magazine?

Federal 55g

Inspect your bolt. Whats your buffer/spring combo.

It is a standard Doublestar adjustable stock with the buffer and spring that came with.

is there a difference in the bolt carrier? like one is a auto bcg and the other is a semi bcg?

They are both semi BCG, mine is an MP and I am not sure what the other was.

To expand a little bit, once I noticed there was a problem I swapped lowers to see if it was maybe a buffer issue as it almost seemed like there wasn't enough pressure to overcome the buffer spring. No change. Then swapped lowers back and disassembled, inspected, reassembled, and swapped bolt assemblies and evrything seemed to be fine. Swapped bolts back and my gun jammed on the first round.

[NYY]

This thing jammed on the second round and would not eject, the brass came out really dirty as well. .

a picture of that

[MUNCHIE]

This is the only picture I have only because I decided to save the first casing

[dieselpower]

my gawd did you find that ammo in the sewer?

My bet is the buffer spring , buffer is junk. remove the buffer, shake it. If it sounds like a babies rattle toss it in the trash can. take out the spring, measure it, 10 1/4" to 11" IIRC is required. remove the extractor spring, is there a donut or spring cushion? Look at the extractor arm, what does the arm look like sharp or dull edges.

[MUNCHIE]

The buffer does make noise when you shake it, I wouldn't descrine it as a baby rattle but it does make noise. Is it not supposed to do that? THis is my first AR and so far has not been so good lol. And no I did not find that ammo in the sewer it is brand new purchsed three days ago and looked great until my malfunctioning gun got a hold of it

[FeuerFrei]

The buffer does make noise when you shake it, I wouldn't descrine it as a baby rattle but it does make noise. Is it not supposed to do that? THis is my first AR and so far has not been so good lol. And no I did not find that ammo in the sewer it is brand new purchsed three days ago and looked great until my malfunctioning gun got a hold of it

The rattle thing is kinda subjective. Depending on what was used to fill it.
Some use metal disks and others use metal shot.
They make a noise. It's okay.
Looks like you already found the problem for your rifle.
When gas is coming back through the chamber and covers the casing you may have a small obstruction in the gas system. Not really a BCG issue.
Is the BC gas key hole dirty or clean? Not enough gas? Very little residue?
Mis-aligned FSB or out of spec gas hole. Gas leak residue at front of gas tube?
Lots of variables here. Get your "good buddy" to swap bolts and narrow down the problem to the bolt or gas system.
Good luck.

[bjl333]

Just a thought !! Did you clean out the barrel before you take it out. The brass look like it burned the powder along with some heavy grease or cosmoline.

[Calgunner217]

Is that from a new upper? Try scrubbing clean the chamber, looks like residue has built up in your chamber and causing casing to stick and not eject.

[MUNCHIE]

Is there a way to tell if the bolt carrier group is the problem or if it is a gas issue? What should I be looking for? I took it apart again last night to clean and lube it but didn't see anything that looks out of the ordinary but with my very limited experience with these guns I am not sure that I would recognize a problem if it was there. How should I go about troubleshooting it? Thanks for all the help

[ir0nclash86]

I was just reading this website about malfunctions. Check it out

http://www.armystudyguide.com/content/army_board_study_guide_topics/m16a2/malfunctions-probable-cau.shtml