Gas and Operating Issues with my Custom Made AR-15

thepatriot

thepatriot

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Hey Guys,

Trying to figure out my problem that I'm constantly having with my Custom Built AR-15.

Background: I got this rifle built for me buy a friend who has been building them and working on them for years, and have had the same problem 3 times now.

My rifle turns into basically a bolt action rifle. It will eject an empty casing after firing, but will not chamber another round, and if it does chamber another round, it normally double feeds.

I've had this problem 3 times now, the first time was a loose gas block, so a quick tighten of the set screws and all was good, until about another 500rounds and then it started doing the same thing. So I took it back to the guy who built it and he completely took apart the upper and reinstalled the gas system and even put in a new gas block and ensured it was all loctited and good to go. Well it was, until last Sunday, I was doing some bench shooting and it was working great, then out of nowhere it started doing the EXACT same thing again, double feeding, and basically turned into a bolt action rifle...which is beyond frustrating.

I do plan on taking it back to the guy who built it and seeing what he says, knowing that he wont be too happy its not working AGAIN. But just wanted to see if there's anyone who has experience in building ARs, that may be able to diagnosis my problem further and give me a few recommendations.

When working, this rifle is a dream to shoot. Low recoil, crisp trigger, and the fit is perfect, but i just can't handle this anymore, and really don't want to have to buy a new rifle.

Thanks in advance,

thepatriot
 
Here's my 2 cents, and it's probably only worth a cent, maybe with change due...

Check the extractor and ejector on the bolt. If there's not enough tension on the extractor or if it is worn, it might be slipping on the case as it tries to extract it. If the ejector is not running smoothly and getting jammed up, it could be that it's not throwing the empty cases out with enough force before the bolt picks up the next round.

Check the gas block again. Regular Locktite breaks down with heat and doesn't really work well on a gas block that gets pretty hot. What direction does the brass eject? Maybe the gas port in your barrel is undersized?

What brand components make up the bolt, barrel and gas block?

If he buit it, he's responsible for getting it running. If it has issues, he should be all too willing to get it sorted out for you.
 
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You haven't given enough info:

extractor spring? buffer? O-Ring?
barrel length?
gas system length?
Chamber type? 5.56/.223/.223 Wylde?
Ammo Type/manufacturer/bullet weight?
buffer type & weight?rifle/carbine/H/H2/9mm?
receiver extension type? rifle/carbine?
 
Wait and let your friend who build it have a look at it first, Like Lee Enfield have posted above there are more than a few scenarios here, without having the rifle in hand, it is hard to tell what is going on.
 
Is it a carbine length receiver extension?
Is it a carbine length spring?
Is it a carbine length buffer?
What length barrel?
What length gas system?
 
mebiuspower said:
Check the gas key to see if it's leaking gas.
Click to expand...

This

Plus check gas block.

If it's a set screw style, it may need the screws staked into position. If it's a clamp-on style, well you may need a higher temp loc-tite to keep from loosening out. I would say try a gas block like the Daniel Defense one that you can roll pin or taper pin into position.
 
All sounds like the gas block or gas key, Because sounds like its moving back or forward cutting off the gas. I know I put a low pro gas block on a barrel that wasn't manufactured for one, so it took alot of measurement to line it up, also leaving a gap from where the FSB would stop on the machined barrel. Downside of clamp on gas block. You could dimple the barrel allowing the setscrew to dig in more, after you replace it. Only takes small amount of movement to block off the gas flow.

Also can make a shim that takes up the gas between the Barrel and Gas Block.

But I also seen people using 2PC handguards non FF handguard systems with clamp on gas blocks, the Spring force of the Delta ring would push the gas block forward. Would work for a bit, and slowly work it self loose.

I also would look on the BGC and see if the gas key on top of the bolt is loose. If it is, tighten and re stake. But really thing its a gas block issue.
 
use red loctite not the blue one. also if the bolt ejects the round but double feeds you should check your gas timing/Key and also the buffer and spring < this depends on your barrel length and your gas tube.also try different mags and ammo to narrow down your problem
 
FYI, Red Loctite breaks down at 260°C.

I'd recommend looking for Flexbar Rocksett High-Temp thread locker which is rated to ~1093°C.
 
Trinimon said:
If he buit it, he's responsible for getting it running. If it has issues, he should be all too willing to get it sorted out for you.
Click to expand...

+2

I would't sell a firearm unless it was working 100%, tested obviously.
For someone to piece together an AR then sell it without firing it is being a terrible person.
 
G37 said:
+2

I would't sell a firearm unless it was working 100%, tested obviously.
For someone to piece together an AR then sell it without firing it is being a terrible person.
Click to expand...

The guy who built it, fixed it twice, so 3rd time, its def the gas block backing off. Maybe the set screw has no bite anymore.
 
Are you running a short barrel? I had no issues until I went to a shorter barrel. I had similar issues with a short barrel (10.5") and standard buffer. Went to a heavy buffer, stronger extractor spring (black o-ring), and that cured some of the issues.

Other problems, included a rough chamber with tooling marks, so the chamber was holding onto a fired case to well, slowing down extraction and then causing a double feed, and jammed up frequently. Also, my smith put in a new Colt bolt, that had a smoother finish then the original that came with the rifle.

Check the gas key... although the one I had was "properly staked" from the factory, it wasn't, and the gas key screws were able to back out considerably, never had that happen before and this was my 3rd AR. I'm not some AR guru, by any means, all I know is now the gun runs fine.
 
You have 2 issues here.

Loose gas block = gas leak. That short strokes the rifle and turns it into a manual action.

Double feed, I assume you really mean Failure to Extract or Eject. Double feed means the magazine allows 2 rounds to pop out, it is a magazine issue

If you have a FTE issue, check the chamber for roughness. If the chamber is good, this means the bolt group is the problem. Replace ejector spring assembly with a good quality one, not some left over in the part bin. Track down the history of the bolt and bolt carrier.

Sorry, the guy who built your rifle got a "F" for not knowing enough to secure a gas block in the first try.
 
Anything cu$tom made needs to go back to whoever built the thing. Mind you, it ejecting but not picking up the next round and double feeding sounds mag related to me too, not gas. Other than using set screws, that come loose on everything(they torqued), the gas system works if it ejects.
 
You can try firing it with only 1 round in the magazine to see if it locks the bolt back.
This will tell you if it if the bolt can go far back enough to pick up another round.
 
There is a good possibility that the gas block hole and barrel hole are not lined up perfectly which would cutoff your gas flow.
This sounds like a flow problem to me.
 
sunray said:
Anything cu$tom made needs to go back to whoever built the thing. Mind you, it ejecting but not picking up the next round and double feeding sounds mag related to me too, not gas. Other than using set screws, that come loose on everything(they torqued), the gas system works if it ejects.
Click to expand...

Custom could also just mean, pieced together.
 
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