AR not ejecting.

clandestine · Jun 1, 2015

It needs to be at least 10" long, .200 in diameter, and ha e a 90 degree deflector.

I may be able to meet up one day and take a look if he can't help.

dist1646 · Jun 1, 2015

Sounds like you have a front sight base with opposing set screws. If the front sight base is locktited, the set screws probably have enough of it on them to require a "lot" of heat to be applied to the fsb before they will turn.

E.Shell · Jun 1, 2015

Kalister1, I have a Hawkeye bore scope and will be in the Millersville area on Mon/Tues, June 8 & 9. If Chad can't get at you, I can bring mine up with me. You could bring your rifle to my office near the Millersville USPO and we can look at it there. Let me know if you want me to bring it up with me.

kalister1 · Jun 1, 2015

clandestine said:
It needs to be at least 10" long, .200 in diameter, and ha e a 90 degree deflector.

I may be able to meet up one day and take a look if he can't help.

E.Shell said:
Kalister1, I have a Hawkeye bore scope and will be in the Millersville area on Mon/Tues, June 8 & 9. If Chad can't get at you, I can bring mine up with me. You could bring your rifle to my office near the Millersville USPO and we can look at it there. Let me know if you want me to bring it up with me.

Thank you very much!
I have one of those jobs that I get to go home when things are done.
I could be in the area @ 5 or 6, depends on the needs of the business.

kalister1 · Jun 7, 2015

I cut the front sight post off of the barrel. Under the sling loop the set screw was in a dimple (Counterbore) in the barrel. There appears to be a ring around the gas hole in the sight block which would indicate the smaller hole in the barrel was well centered.

I installed a low profile gas block to fit under a free float tube. If that does not fix it, that leaves the gas tube and chamber?

It appeared to me that there was (Crud) on the outside of the gas tube. Does any type of sealant belong on the tube?

dist1646 · Jun 7, 2015

Are you sure you have a carbine buffer and not a pistol buffer?
The crud on the outside of the gas tube is carbon blow by. It is normal to see some degree of carbon build up due to blow by. It is possible that the hole for the gas tube is oversize. Since you are replacing it, I wouldn't worry about it.

kalister1 · Jun 7, 2015

Yes, Carbine buffer.
This upper fails on the same lower that an identical upper runs fine on.

dist1646 · Jun 7, 2015

After re-reading the entire thread, I suggest taking it to a gunsmith who knows AR's.

outrider58 · Jun 7, 2015

I'm running a carbine buffer in my pistol without any hick-ups. It eats everything I feed it. From M855 to plinker reloads.

I do agree with dist1646, take it to a smith for a hands on look-see.

E.Shell · Jun 8, 2015

dist1646 said:
dist1646 said:

After re-reading the entire thread, I suggest taking it to a gunsmith who knows AR's.

Click to expand...

outrider58 said:

...I do agree with dist1646, take it to a smith for a hands on look-see.

Click to expand...

This is going to ruin any chance of further speculation and guess work, how can you guys even go there?

outrider58 · Jun 8, 2015

E.Shell said:
This is going to ruin any chance of further speculation and guess work, how can you guys even go there?

Click to expand...

There's always this:

http://www.mdshooters.com/showthread.php?t=176082

kalister1 · Jun 8, 2015

E.Shell said:
This is going to ruin any chance of further speculation and guess work, how can you guys even go there?

Click to expand...

Don't stop my fun. I like to play with my toys.

outrider58 · Jun 8, 2015

kalister1 said:
E.Shell said:

Don't stop my fun. I like to play with my toys.

Click to expand...

Long as you keep breaking them, we'll be hear for ya!

kalister1 · Aug 1, 2015

I finally got it to the range.
I replaced everything possible, new gas block and tube was the last thing to try and it did nothing.

So I came to the conclusion the barrel was at fault. Before replacing it I used a 30 caliber bore mop with some valve lapping compound to polish the chamber. It now throws empty cases several feet in front of me. My other upper (Both 16") throws them to the side an back. I have seen other guns throw empty cases forward, so as long as it runs it can throw them anywhere it likes.

I did not mic the empty cases but did not see any signs of extreme bulging.

Can anyone shed some light on why guns shed brass in different directions?

rgramjet · Aug 1, 2015

I had a similar issue with my LAR 8. Consistent failure to eject. Sent it back to Rock River and they found a gas tube issue. I think it worked itself out.

Since getting it back, it has performed flawlessly.

clandestine · Aug 1, 2015

Where it throws brass is not an exact science. Forward indicates it's overgassed, but that isn't always the case.

Adjustable Gas will assist.

outrider58 · Aug 1, 2015

kalister1 said:
I finally got it to the range.
I replaced everything possible, new gas block and tube was the last thing to try and it did nothing.

So I came to the conclusion the barrel was at fault. Before replacing it I used a 30 caliber bore mop with some valve lapping compound to polish the chamber. It now throws empty cases several feet in front of me. My other upper (Both 16") throws them to the side an back. I have seen other guns throw empty cases forward, so as long as it runs it can throw them anywhere it likes.

I did not mic the empty cases but did not see any signs of extreme bulging.

Can anyone shed some light on why guns shed brass in different directions?

So, have the failures stopped?

kalister1 · Aug 1, 2015

Yes, ran 4 magazines (standard) through without a failure.

outrider58 · Aug 1, 2015

kalister1 said:
Yes, ran 4 magazines (standard) through without a failure.

Sounds like you fixed it!

What was the cause of the problem...for those of us who are trying to learn?

kalister1 · Aug 2, 2015

I am going to say a ruff chamber.
The last thing I did was polish it with a 30 caliber bore mop and valve lapping compound. I spun it with a drill (SLOW) and stopped when I could tell a difference in the "SHINE" of the chamber.
I measured the gas hole in the barrel @ .085" and from what I have read a 16" barrel should be .07?' to .086"

AR not ejecting.

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