Fail to feed, eject, and fire

[minnesotamulisha]

Ok, here goes. I finally have my rifle put together. I went to the range tonight and the gun wouldn't cycle. Here's what I have in the rifle:

Rainier Arms Lower
Wilson Combat Upper
Wilson Combat LPK
Core15 BCG coated with Nickel Boron
Giessele Super Dynamic-Enhanced Trigger
Black Hole Weaponry 18" LTR Rifle Length Barrel
Battle Tested Equipment micro Adjustable Gas Block
Midwest Industries SS Gen 2 15" Hand Guard
Ares Arms EFFIN-A Compensator
Magpul PRS stock
Rifle Buffer
Yankee Hill Machine Rifle Length Gas Tube
Magpul 20 and 30 rd. PMAGS
I forget the brand of the buffer tube and spring

I am shooting PMC X-TAC 55 grain, brass cased ammo. These are FMJ rounds.

When I got to my shooting spot, the gas block (being adjustable) was almost closed. I fired a round and the casing ejected, but it did not load another round into the chamber. I cycled the gun manually, opened the chamber on the gas block, and tried it again. Same thing. I repeated this until the set screw was about to fall out of the gas block. Consistently, the new round would not load into the chamber. After five rounds, I would take the gun apart, clean the barrel per the barrel break in recommended on this forum, then I would start again.

I fired a total of 70 rounds. 3 times out of 70, the rifle cycled properly. The rest were manually loaded.

Some times, the round would load, but I would have to use the forward assist in order to get the round chambered, as if the bolt was stuck and wouldn't push the round into the chamber fully. Other times, the bolt would cycle, but it never picked up the next round.

I used Weapon Shield brand grease and oil and applied amounts according to this: www.ar15.com/mobile/topic.html?b=3&f=7&t=548967

All lubricants were applied yesterday and the gun was cleaned before hand.

Does anyone have any info on why the rifle won't cycle? Anything would help at this point. I do have a carbine buffer and a different buffer spring.

I just thought of something. While I was shooting, I was resting the magazine on the shooting bench as I don't have a bipod yet. Is there a chance this could have a negative effect on the cycling of the rifle?

I was shooting at 25 yards as I thought I could dial in the scope during break in. Not having a proper rest, it wouldn't have been great, but at least close for when I move out to a hundred yards.

Attachments:

[GLSHOOTER]

The mag resting COULD be a factor. That being said I am going to blame the buffer spring. I bet if you clip a few coils off of it and try it you will be closer to what you need. The BCG may well not be coming back quite enough to get behind the new round.

You didn't mention if it would lock back when you fired it single shot. Did you try that? With the port wide open and if it did not lock back then the spring stacking up would almost have to be the culprit.

Greg

[minnesotamulisha]

Yes, I forgot to mention that the bolt would NOT lock open after emptying the mag. I'll cut off a few coils and see what happens. It may be a while before I get back to the range, but I'll definitely keep you updated.
Thanks for the help, Greg!

Adam

[minnesotamulisha]

What if I set my gas block up against the shoulder on the barrel. Would that cause a misalignment between the gas port in the gas block and the gas port in the barrel?

[gunmutt]

The gas block could cause that. If the port is eclipsed by the block then you would not have enough gas. It happened on my 5.56 as well. The one thing I really like about my new Noveske Barrel is that the gas block is pinned from the factory to ensure alignment

[GLSHOOTER]

Mar 30, 2013 4:24:05 GMT -8 minnesotamulisha said:

What if I set my gas block up against the shoulder on the barrel. Would that cause a misalignment between the gas port in the gas block and the gas port in the barrel?

Yep that could be an issue. Get the calipers out and start looking at the hole alignment. Most of the adjustables have a good hole size for adjustment slop but yours may be on the small end.

Greg

PS: Check the hole for the gas port and make sure that it is completely clear. Sometimes a burr may be left in the hole after the first shot. Also make sure the gas key is not leaking.

[minnesotamulisha]

Thanks for the info, Greg. Yesterday I removed the gas block from the barrel and I didn't see any witness marks that would suggest the holes were out of alignment. I used the calipers for determine what would be perfectly center and now the gas block is no longer riding the shoulder on the barrel. I moved the gas block about .025" toward the muzzle.

I also looked in the gas port of the barrel and the gas block and didn't see anything that looked to be obstructing either one.

How would I tell if the gas key was leaking? The bolt does have some dirt on it from the gas, but being this is my first AR, I don't know if it is an excessive amount.

[GLSHOOTER]

Mar 31, 2013 5:54:12 GMT -8 minnesotamulisha said:

Thanks for the info, Greg. Yesterday I removed the gas block from the barrel and I didn't see any witness marks that would suggest the holes were out of alignment. I used the calipers for determine what would be perfectly center and now the gas block is no longer riding the shoulder on the barrel. I moved the gas block about .025" toward the muzzle.

I also looked in the gas port of the barrel and the gas block and didn't see anything that looked to be obstructing either one.

How would I tell if the gas key was leaking? The bolt does have some dirt on it from the gas, but being this is my first AR, I don't know if it is an excessive amount.

Sounds like you moved it ahead just enough. Most blocks we use do not fit flat on the shoulder.

First off check the key bolts for tightness. If they are GTG look at the juncture of key/carrier. You may see some blow by. I'm willing to bet, thanks to a long talk with Ritch on this, that the GB location will be the key. I haven't run into any factory installed keys that were lose but it is not unheard of.

Greg

[minnesotamulisha]

I've got good news. Last night, I made it to the range. Everything cycled properly and I went through a 20 rd mag in no time, with no issues what so ever! Thanks to everyone on this page so helping me out! Not only did it save me a few bucks not having to take it to a gun smith, but I learned a little more about the AR platform. Thanks again! ;D

Also- When I get some new rings, I'll post a range report.

[AndyBHW]

Please do. I would love to see how this set up prints. There is a lot of great information to be shared here. Nice job diagnosing the issue Greg.

[dr69er]

There is usually a .015" gap at the gas block journal shoulder
on a AR-15 barrel, so who ever mentioned there is a gap
was correct.

One other note, it is fairly common to have a gas block
misaligned just engough to cause short stroking Issues
so always check that before enlarging the gas port
diameter and such.

Glad everything worked-out.