Gas key leaking?

[Nico9283]

A friend of mine is trying to convince me that getting fouling on the first 3-4 inches of the outside of your gas tube where it meets the key on the bcg is an indicator of a bad fit between the gas key and the gas tube. Am I wrong in thinking that this is not only completely normal, but literally unavoidable and an inherent part of the way a gas system operates??

In the picture below, I am under the impression that some gas will naturally travel in the direction of the arrow as soon as the bcg moves backwards far enough to loose contact with the gas tube. Who’s the idiot, me or him?

 

[Compooky]

Never really paid attention to this. Just looked at a couple of mine and they’re pretty clean. All the carbon on the tube is on the section that sits in the gas key.

 

[sschevy]

completely normal

Keep the gas key , replace the friend

 

[Drix]

While I haven't checked mine, where does he think the gas is going to go when the bolt unlocks and slides rearward?

 

[Nico9283]

While I haven't checked mine, where does he think the gas is going to go when the bolt unlocks and slides rearward?

His argument is that by the time the bcg moves back far enough to lose contact with the gas tube, gas should be done coming down the gas tube. And while that may be true.. my argument is that there’s going to be some residual low pressure gas still escaping the system.
Maybe he’d have a point if this area was getting caked after 100 rounds. But I feel like “just a quick wipe” after about a thousand rounds is not reason to fret.

Glad everyone seems to agree… I wasn’t going to have an easy time apologizing for being wrong lol.

 

[JDL]

No not a problem, normal.
Think about this. If the gas key was so tight on the gas tube to not carbon up it would have to be so tight that the bolt would not be pushed back.

 

[whacko]

A friend of mine is trying to convince me that getting fouling on the first 3-4 inches of the outside of your gas tube where it meets the key on the bcg is an indicator of a bad fit between the gas key and the gas tube. Am I wrong in thinking that this is not only completely normal, but literally unavoidable and an inherent part of the way a gas system operates??

In the picture below, I am under the impression that some gas will naturally travel in the direction of the arrow as soon as the bcg moves backwards far enough to loose contact with the gas tube. Who’s the idiot, me or him?

View attachment 832710

I've cleaned enough m16 and m4 rifles in my 25 years in the army to know for sure that there was always some carbon on the outside of the gas tube. Always.

Tell your friend he's a pog piece of shit ignorant ass.

 

[Nico9283]

I've cleaned enough m16 and m4 rifles in my 25 years in the army to know for sure that there was always some carbon on the outside of the gas tube. Always.

Tell your friend he's a pog piece of shit ignorant ass.

gonna show him this directly, I’ll let you do the honors