BCM gas tube wear, is this normal?

[Glock9mm1990]

So I noticed upon inspecting my BCM midlength upper that the gas tube at the very end has some shiny wear marks at the very end of the tube. I checked the gas block alignment and it is perfectly straight, I also did the gas tube alignment test by taking the bolt out of my bcg and letting it slide home under its own weight and it went in just fine with no binding. I’m just curious if this is normal or should I be worried?

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This upper is a complete BCM upper with 270 rounds through it with no malfunctions, I should also point out I have another BCM upper that shows the same thing with around 800 rounds again with no malfunctions. So is this normal? Thanks for any input.

[tehpwnag3]

It's probably just fine. If in doubt, strip down the BCG and just insert the carrier into the upper (no bolt or charging handle). If you feel any binding, you can tweak the gas tube slightly. There are instructions and video online on how to do this. Note that there will be some rubbing, but it should be barely noticeable.

[markm]

Is the outer diameter of the gas tube at the fat tip that goes into the key wearing fast? I've had to replace 2 middy gas tubes the wore out there because gobs of gas was leaking out and causing weak cycling. I believe there were a run of middy tubes that were bad.

[Glock9mm1990]

It's probably just fine. If in doubt, strip down the BCG and just insert the carrier into the upper (no bolt or charging handle). If you feel any binding, you can tweak the gas tube slightly. There are instructions and video online on how to do this. Note that there will be some rubbing, but it should be barely noticeable.

Yeah that’s what I did and the bcg went in no problem with no binding.


Is the outer diameter of the gas tube at the fat tip that goes into the key wearing fast? I've had to replace 2 middy gas tubes the wore out there because gobs of gas was leaking out and causing weak cycling. I believe there were a run of middy tubes that were bad.

Not that I can tell.

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[markm]

That looks good. I had some that were worn nearly flat/flush with the diameter of the tube.

[Glock9mm1990]

That looks good. I had some that were worn nearly flat/flush with the diameter of the tube.

So nothing to worry about then?

As for the ones you had that were worn down, did they still function 100%?

[tehpwnag3]

I think you're fine. If you experience any cycling issues, replace the gas tube or have a good AR guy take a look.

[Glock9mm1990]

So I’m an idiot.:laugh: Turns out that the so called wear is just areas where the carbon fouling is rubbing off, because I don’t clean my guns.