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6/6/2013 5:56:02 PM EDT
I'm sure multiple links have been posted on this subject. If someone would be so kind and add them in a reply.
I put this 20 inch together and went to the range today.
The rounds are failing to eject.
They aren't stove-piping.
When the round fails to eject I look inside and the round is still inside.
I used the same mag in another AR I had with me and it worked fine. I also used a Troy Battle Mag with the same results.
I switchedout the buffer spring and got the same FTE.
The buffer spring that was in the rifle worked fine in the other gun.
The top pic is the rifle. The second pic is the gas hole in the barrel. The third pic is the space between the low profile gas block and the ledge on the barrel. About a Dime's width. The last pic is the buffer.



6/6/2013 6:15:38 PM EDT
[#1]
Does your gas block not cover the gas port?
6/6/2013 6:17:49 PM EDT
[#2]
Quoted:
Does your gas block not cover the gas port?


That's what I'm wondering. I leave the space to account for the missing hand-guard retention plate. So it should be lined up. The quad is a free float so no plate. Maybe I left too much space?

6/6/2013 8:22:29 PM EDT
[#3]
Blow air into the muzzle.  Seal up the chamber.  Do you get feed from gas tube???
 
Or just break out some calipers.
6/7/2013 12:41:32 AM EDT
[#4]
Some of the low profile gas blocks just butt up to the shoulder on the barrel. You don't need to leave a gap which may be part of your problem.
By leaving the gap you may be blocking the port.

Hope this helps.
6/7/2013 2:47:39 AM EDT
[#5]
I'll check her out this am andwe'll see what's up. Thanks .
6/7/2013 4:51:55 AM EDT
[#6]
Quoted:
I'll check her out this am andwe'll see what's up. Thanks .

"and the round is still inside"

Do you mean fail to extract ?

Does the bolt lock back on the last shot over an empty mag ?

Always use full power ammo like Lake City XM193 or M855 for initial testing.

6/7/2013 7:10:46 AM EDT
[#7]
The spent cases are not ejecting, or the bullet is still lodged in the barrel?  

You might be partially blocking your gas port like previously stated, move the gas block back to the shoulder.

Also with the block forward (even just a bit like that) the other end of the gas tube might not be making good contact with the carrier key and you might be getting some blow by there.

The two things could be compounding upon each other causing your problems.

6/7/2013 8:17:55 AM EDT
[#8]
Does the bolt cycle at all after you fire?

Im assuming it doesn't how you said your not getting a double feed and the FTE. Only reason I ask is because I had an M4 while serving that failed to cycle/FTE and it was because the forward assist was blocking the BCG from moving rearward.
6/7/2013 10:22:25 AM EDT
[#9]
I was using Federal match ammo. The casing was not in the chamber it was in the receiver. The bolt did not lock back on the last round. I did have this problem in the past when shooting Tula out of an older gun. Is it called short-stroking? That's why I thought it wasn't getting enough gas but always want opinions.
6/7/2013 12:38:42 PM EDT
[#10]
based on the gas port in the barrel, you're not exactly centered up, but i would think you are getting the full measure of gas back to the receiver.
based on the picture of the gas port, you can probably scoot that gas block back to the edge of the barrel notch.


didn't someone about a month ago have a similar problem that was fixed by replacing the extractor spring?
6/7/2013 5:47:44 PM EDT
[#11]
Quoted:
based on the gas port in the barrel, you're not exactly centered up, but i would think you are getting the full measure of gas back to the receiver.
based on the picture of the gas port, you can probably scoot that gas block back to the edge of the barrel notch.


didn't someone about a month ago have a similar problem that was fixed by replacing the extractor spring?


I'm just gonna take it apart and break out the caliper..

6/7/2013 5:47:55 PM EDT
[#12]
Quoted:
I was using Federal match ammo. The casing was not in the chamber it was in the receiver. The bolt did not lock back on the last round. I did have this problem in the past when shooting Tula out of an older gun. Is it called short-stroking? That's why I thought it wasn't getting enough gas but always want opinions.

Yes, your symptoms point to an under-gassed condition commonly called "short-stroking".
If this Federal Match Ammo is .223, and your rifle is set up for full power 5.56, the lower pressure .223 ammo may not be able to run it.

6/7/2013 6:02:37 PM EDT
[#13]
Quoted:
Yes, your symptoms point to an under-gassed condition commonly called "short-stroking".
If this Federal Match Ammo is .223, and your rifle is set up for full power 5.56, the lower pressure .223 ammo may not be able to run it.


thanks

6/14/2013 8:06:18 PM EDT
[#14]
I switched out the gas tube and slightly readjusted the gas block again. Now she runs like clockwork.
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