10.3 DD with A5 system

[sig1473]

Ok, I did that, and yes the set screw hole aligns perfectly with the gas port. I went ahead and tried my upper with another lower and it worked fine.

Did everybody not read this?

[elpotro]

SIG1473
I forgot to explain that this particular lower that I tested did not have a green sprinco and this is also when I had a spent case with a live round jam indicating the poor extraction. I apologize for not explaining this more clearly. When I get home I will check for a leaky gas Key. But first I will replace the extractor spring and use a functioning BCG. I am learning... I did not know that for SBR I needed a better extractor spring. By the way I did contact BCM and they have been very helpful.

[RHINOWSO]

Did everybody not read this?

Lol, hilarious...

My guess is troll, likely a PtMCcain type, although I don't detect as much smug arrogant a$$muncher when he is around.

Anyway, pass the popcorn.

[elpotro]

Ok!

I came home and this is what I did: I picked up the BCG and put oil around the gas key where it meets the Bolt Carrier. I then proceeded to shoot some air from a compressed gasduster into the gas key and there is a tiny corner where bubbles present themselves. Is this enough to call it a leak that would cause a malfunction? I tried the same thing on two other BCG and there were no presence of bubbles. In your experience, is this a leaky gas key? I don't have much experience with this forum or with troubleshooting AR's, so I am grateful for the advice and the questions to pin point the issues.

Thanks

[Leonardo]

A leaking gas key with 100psi will leak a great deal more when shooting

[elpotro]

Thank you!

[TonyAngel]

I don’t know if I missed it, but did you try a known, working BCG? Even when ordering the best of parts, there’s always a chance that you’ll get a dud.

Yeah, sounds like a gas leak. It may even be such that it gets worse as things heat up. The gas system operates at around 50k psi. I can only imagine what leaks out at that pressure.

It seems that the easiest test would be to replace the BCG and try it out.

[elpotro]

I don’t know if I missed it, but did you try a known, working BCG? Even when ordering the best of parts, there’s always a chance that you’ll get a dud.

Yeah, sounds like a gas leak. It may even be such that it gets worse as things heat up. The gas system operates at around 50k psi. I can only imagine what leaks out at that pressure.

It seems that the easiest test would be to replace the BCG and try it out.

I am going to do several tests, one by one, to check. I learned via this thread that I was thinking about too many things and trying to shotgun the solution. That is not a good idea. I am waiting for a sprinco extractor. If that does not work I will try a new gas tube. If that does not work I will throw in a new BCG. This is part of the fun. Frustrating at the beginning, but still fun. Embrace the suck LOL

[TonyAngel]

No, man. Throwing parts at it is the worst thing to do. Have you tried a known to be working bolt/carrier group? You've already located a gas leak at the gas key. If it's leaking that much, replacing the extractor isn't going to determine anything except that you've learned to replace an extractor.

I once built an AR using a very properly gassed barrel. I used a cheap adjustable gas block because it was what I had. The gun kept short stroking. In the end, it turned out that the gas block itself was leaking enough gas to keep the gun from running properly.

If your leaking gas key is causing a similar situation, you're wasting your time. The new BCG that you bought is defective. Changing all of the parts on the gun ain't gonna make it run if it's the gas leak making it stumble.

If you're just in the mood to spin your wheels, I suppose you could try putting some red loctite around the area where the gas key is leaking and see if it runs any better. Let the loctite dry of course, before you try it; but it may seal up the leak for a bit to see if it will run right. Have you tried putting a wrench on the gas key screws to see if they are loose? They may not have been staked properly.

[Diamondback]

I am going to do several tests, one by one, to check. I learned via this thread that I was thinking about too many things and trying to shotgun the solution. That is not a good idea. I am waiting for a sprinco extractor. If that does not work I will try a new gas tube. If that does not work I will throw in a new BCG. This is part of the fun. Frustrating at the beginning, but still fun. Embrace the suck LOL

Jump straight to the BCG Swap, it's easier. Pop 'n' Drop as opposed to tearing the whole URG apart to swap a gas tube. Easier steps first, more difficult as escalations after.

EDIT: Belay that, check the key screws and if it's properly cinched-down and staked and STILL leaking then swap the BCG's.