AR Problems

Patriot

Patriot

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I'm shooting reloads in my AR which operated fine in my other one, but this one seemingly is much 'tighter'. Upon
firing the bolt does not move to the rear all the way. The upper is the AA group buy, and the rest of the upper
components are White Oak supplied, including the BCG. The lower is AA with a Stag LPK. The reload I am using is
a 55gr jacketed rounds pushed by 25,0gr of either 2230 or H335.

Notable items:

1) The spring in the buttstock makes a noticeable twang whenever the bolt returns..
2) The bolt doesn't lock back with an empty mag
 
load up a bunch of mags with 1 round in each. If the gun fails to lock back on the mags you most likely have a gas issue.
 
25.0 of H335 is not underpowered.

Does the gun run on factory ammo OK?

Do you have a gas leak at the block or key?

Will an unfired rounds eject smoothly?
 
Supermoto said:
25.0 of H335 is not underpowered.
Click to expand...

Agree with Supermoto. If this is a 18" barrel that combo is probably producing 3000 fps.

Notable items:

1) The spring in the buttstock makes a noticeable twang whenever the bolt returns.. - This is normal. Some grease on the spring or moving to a CS spring will dampen the twang.
2) The bolt doesn't lock back with an empty mag - As others have said, sounds like a gas problem. Check to see if the gas block moved, any leaks, tube is blocked or gas key isn't staked.
 
Supermoto said:
25.0 of H335 is not underpowered.
Click to expand...

Does the gun run on factory ammo OK?
Click to expand...

I didn't have any at the range but my guess is that the same condition will exist. Sometimes
it will cycle, most times it won't.

Do you have a gas leak at the block or key?
Click to expand...

Good question. I don't know. Is that something I can diagnose without taking the gun apart?
Any external symptoms?

Will an unfired rounds eject smoothly?
Click to expand...

Yes. Also, it will never lock open on an empty mag except when I manually
cycle the bolt. I have done a cleaning prior to this time and the system is
very 'wet' so I don't think that is the issue. Prior to this I was using Brian
Enos Slide Guide and I didn't like that way it seemed to collect the dirt and
grime so I went back to oil. A gas problem sounds like it might be the culprit.
What the heck can go wrong with the gas system? I built this upper myself
so now I am questioning all (any) of my mechanical skillz.

Interestingly enough, I hadn't shot this rifle since last spring (2010) and
at the time it functioned just fine (with the same reloads). When I got it
out a couple of weeks ago it never functioned correctly.
 
zerodown said:
Agree with Supermoto. If this is a 18" barrel that combo is probably producing 3000 fps.
Click to expand...

It's the White Oak Armament CMP Match Barrel. I believe it is an 18" barrel.

Notable items:

1) The spring in the buttstock makes a noticeable twang whenever the bolt returns.. - This is normal. Some grease on the spring or moving to a CS spring will dampen the twang.
2) The bolt doesn't lock back with an empty mag - As others have said, sounds like a gas problem.

Check to see if the gas block moved, any leaks, tube is blocked or gas key isn't staked.
Click to expand...


OK, thanks for the info.
 
Last edited:
silly question and it may not be relevant but how'd you install the barrel if you installed it yourself? i've seen uppers that were just crammed into a bench vice for putting on a barrel get squished and end up slightly smaller causing a similar issue to what you're describing.
 
Take the gas block off and spray some soapy water around the area the gas tube goes into the block, then blow into the tube while covering the gas port in the block with your finger. I bet you will see bubbles around the gas tube where it enters the gas block. If you do this will most likely be your problem. Drive the pin out and remove the gas tube, clean the end up and clean the gas block. Put some type of sealer on the gas tube, the part of the tube that goes into the block. I use Sally Hansons Hard as Nails, however any type of sealer will work. What you are trying to do is seal the gas leak around the gas block. While the sealer is still wet put the gas tube back into the block and line the pin hole up with a small punch or anything that will fit in the pin hole to keep it lined up. Let the sealer harden up before you reinstall the pin. This very small gas leak will cause short stroking.
Two other areas to look at would be the Bolt gas rings make sure they are not lined up and make sure the gas key isn't loose.
If you still have a problem after you seal the leak change your buffer to a H buffer even if you are using a rifle buffer now you can change to a carbine H buffer.
Please let me know how you make out.
John
 
Last edited:
Remsport Mfg said:
Take the gas block off and spray some soapy water around the area the gas tube goes into the block, then blow into the tube while covering the gas port in the block with your finger. I bet you will see bubbles around the gas tube where it enters the gas block. If you do this will most likely be your problem. Drive the pin out and remove the gas tube, clean the end up and clean the gas block. Put some type of sealer on the gas tube, the part of the tube that goes into the block. I use Sally Hansons Hard as Nails, however any type of sealer will work. What you are trying to do is seal the gas leak around the gas block. While the sealer is still wet put the gas tube back into the block and line the pin hole up with a small punch or anything that will fit in the pin hole to keep it lined up. Let the sealer harden up before you reinstall the pin. This very small gas leak will cause short stroking.
Two other areas to look at would be the Bolt gas rings make sure they are not lined up and make sure the gas key isn't loose.
If you still have a problem after you seal the leak change your buffer to a H buffer even if you are using a rifle buffer now you can change to a carbine H buffer.
Please let me know how you make out.
John
Click to expand...

Well,

I have just about had it with the rifle. I tried your suggestions - didn't work. I then took it to ZHA where they replaced the gas tube
and did $100 worth of work - works better, but the problem is fundamentally the same, short stroking. The rifle as constituted shoots
great. As accurate as I could possibly want, if I wanted a single shot AR because that is what it is for all intents and purposes.

I am guessing that the upper components that I purchased from WOA are industry standard but not compatible with the AA stripped
upper I purchased. I'm guessing that a different stripped upper might make this setup work but I am not going to get in to it. I have
had it. I'm going to sell it either as a fixer-upper or part it out.

What a cluster-**** this whole experience has been. If I never see another AR it will be too soon. The rifle probably has less than
500 rounds through it;.
 
Last edited:
That sucks. Did you try factory ammo?

How about the buffer and the spring? When installing the spring add a LIGHT coating of grease on the spring. There are a lot of cheap *junk* buffers.

Does you butstock have a screw with a hole in it to less the gas escape? If you use a screw without a hole on the end of the gas tube it will short stroke.
 
Last edited:
The first thing I would look at is the buffer spring and buffer. Are you running a carbine stock with a rifle spring and / or buffer? (Yes, there is a difference.)
 
Another_David said:
Does you butstock have a screw with a hole in it to less the gas escape? If you use a screw without a hole on the end of the gas tube it will short stroke.
Click to expand...

Pretty sure that's to let water drain out of the buffer tube....
 
couple other things to check

gas tube alignment. take the upper off, take the bolt out of the BCG, and manually run the BCG back and forth. is the gas tube centered up and entering the gas key smoothly? I've seen slightly misaligned gas tubes before, and if they're tighter on one side than the other, it wears down that "bulb" on the end VERY quickly, leading to a gas leak.

is it a rifle length buffer tube? (if so, I've got a couple of brand-new never used buffers and buffer springs that you're welcome to try out...see if thats your issue.


can you lock the bolt/BCG back COMPLETELY by hand? I watched a buddy of mine struggle with what appeared to be short stroking, turns out he used the wrong bolt to screw his buttstock on. bolt was sticking into the buffer tube JUST a little bit...but it was just enough to keep the buffer from riding all the way to the rear.

gas leak @ the front sight base. they all leak a little bit, and are usually self sealing (the carbon builds up and seals itself quite well. cheap insurance is a LITTLE BIT (I stress, a LITTLE BIT) of #209 wicking loctite around the rear band. use too much, and it can get into the gas port.

gas will leak around the opening in the gas block where the tube is pinned in. same as with the rear gas block band....doesnt matter. if it leaks, it'll seal itself up inside of 100rounds.


**just re-read up above. make you an offer, since I know you're a good dude.

give me the upper for a weekend. I'll go through it. I'm willing to get I can get it running like a top, and I'll hand it back to you free of charge. I've got enough spare parts kicking around that it ought to be a quick fix. I maintain my own match rifles, (changing at least 1 barrel a year), and put 3-5000 rounds through them a season. I've yet to have one not run like a top.
 
Last edited:
I would think either a gas tube alignment issue, or the gas port in the barrel is out of spec. This happened to me with a Daniel Defense barrel. I had to open the hole up a bit and now it works like a charm.
 
glide said:
I would think either a gas tube alignment issue, or the gas port in the barrel is out of spec. This happened to me with a Daniel Defense barrel. I had to open the hole up a bit and now it works like a charm.
Click to expand...


John's 18 and 20" CMP and DSM/match barrels (the one's on Wilson blanks) are all profiled/chambered/drilled on a CNC. theres no real possibility of a gas hole being out of spec. plus, I have a few of his barrel's on the shelf, and they're all right on where they should be. I'm willing to bet this is an easy fix.



Patriot: What are you using for a buffer tube and stock? if you used an A2 stock, are you sure you've got the right screws in the right holes? (one is longer than the other)
 
Last edited:
I had an upper do the same thing a while back, and it was the gas rings. Pull the carrier, extend the bolt, place the carrier assembly on your bench bolt face down. If the bolt slides into the carrier, replace rings
 

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