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[shawn3210]

Hey guys, just finished my ar-15 build and took it shooting yesterday. Shot pretty good except I was having issues with the casing getting jammed every other mag....annoying problem. I was using pmc 223 ammo from ammo bros. Not sure if it's the ammo or the mag? Any suggestion? I have a jbo gbc.

[pwnage]

Need a little more info.

When you say "the casing is getting jammed" do you mean that the casing is failing to eject all the way or that the casing isn't even being extracted from the chamber?

[shawn3210]

it's failing to eject all the way. It would get stuck in the chamber

[Fritz265]

Sounds like a gas problem

[pwnage]

Could be a gas problem but maybe not.

So when the casing gets stuck, is another round fed? Is the casing still in the bolt face when the jam occurs or does the round come loose in the action?

A couple of suggestions. Cycle the action with some dummy rounds. Go through an entire mag to make sure that all the rounds feed and eject properly. If they do then your extractor is working as it should and as Fritz265 mentioned, you might have a gas problem.

If its the case that the casing is separated from the bolt face and left in the action/chamber then the extractor is not tight enough to hold on to the round and pull it fully from the chamber.

You can check for a gas issue by using a different ammo. If your barrel is rated for 5.56 I would try some of that as it has a higher pressure than .223. If that works then ammo was your problem and I would go back to another brand of .223, then again if you can use 5.56 you could just go with that and call it a day.

[Munny$hot]

Type of ammo and where is your brass ending up on the ground (barrel 12:00/Butt stock 6:00)?

[gun toting monkeyboy]

I know this is a silly question, but how did you have it lubed? You can sometimes get FTE or FTF issues from not having enough lube on the different bearing surfaces. Especially on a new gun that hasn't worn off all of the rough edges yet. Have you tried lubing it up and seeing if that resolves the problem?

-Mb

[shawn3210]

Gonna use the 556 federal round this weekend and see how it goes.

I was using pmc 223 55 grain that I picked up from ammo bros.

[Fritz265]

It's not the ammo

[ar15barrels]

PMC ammo is notably problematic in new guns.
Break the gun in with a few hundred rounds of good brass cased 5.56 ammo.
Lube it well.
After that, it should work with PMC.

[proraptor]

Pmc is good to go, ive been using it in my ar since the beginning

[ar15barrels]

It's not the ammo

It's the combination of weak ammo AND a new gun.

Pmc is good to go, ive been using it in my ar since the beginning

Depends on the gun.
You have NOT been using it in the OP's gun since the beginning without problems so you can't really say if his gun works with it or not.

[Fritz265]

It's the combination of weak ammo AND a new gun.



Depends on the gun.
You have NOT been using it in the OP's gun since the beginning without problems so you can't really say if his gun works with it or not.

True. Maybe I'm just spoiled with a Sig

[ar15barrels]

True. Maybe I'm just spoiled with a Sig

Comparing an AK to an DI AR in it's ability to run crappy ammo is funny.
AK's are DESIGNED to run crappy ammo.
They have a big gas piston to help them run...

[Fritz265]

Sig 516 is an AR. Albeit piston rather than DI