Let's talk gas tubes for a sec

Yarome · Aug 26, 2022

In practical terms and for the average avid shooter, is there really a difference? Other than the obvious... straight, well formed and fitting key interface... what sets one tube apart from the others? Not that they are all that spendy or even fail with any regularity, but it's one element of my rifles I admit I haven't done much research on. Have I been overlooking a key element, or... as long as you get gas when you want it, who cares type situation?

On full part by part builds I've generally spent a little more.. say, like for Lantac's or similiar... but I have my share of "PSA" level uppers with OEM provided tubes too.

I've only had 1 tube ever fail on me. It wasn't one of the "budget" builds, though and the blowout was well deseved. Don't ask.

Some questions come to mind.

Can degredation be measured? What to watch for? What's a reasonable life expectancy? Only replace as needed or is there a round count where a person might consider swapping a functional tube out to ensure future reliability?

If you are choosy about your tubes, what exactly are you looking for when deciding and why?

msgriff · Aug 26, 2022

The torture test videos that I've seen (continuous full auto until failure), it's always ended with gas tube failure. I wouldn't expect to see that failure in real life, including with normal full auto rate of fire. Misalignment does cause the end bell to wear out faster causing short stroking. They do make gauges to measure tube wear, also gas key wear gauges. I like the black nitrided stainless steel tubes, but the standard SS ones should outlast the barrel. I've seen some no-name cheap ones that I wouldn't use, they look like they were cut with a tubing cutter and not reamed. I never re-use gas tube roll pins. There are some high round count (30k+) articles/threads around, I don't remember any gas tube failures in any of the properly built firearms.

DLS · Aug 27, 2022

I swap the tube when I swap a barrel. Just 'cause ... provably don't need to but why not? They are inexpensive.

titsonritz · Aug 28, 2022

msgriff said:
The torture test videos that I've seen (continuous full auto until failure), it's always ended with gas tube failure. I wouldn't expect to see that failure in real life, including with normal full auto rate of fire. Misalignment does cause the end bell to wear out faster causing short stroking. They do make gauges to measure tube wear, also gas key wear gauges. I like the black nitrided stainless steel tubes, but the standard SS ones should outlast the barrel. I've seen some no-name cheap ones that I wouldn't use, they look like they were cut with a tubing cutter and not reamed. I never re-use gas tube roll pins. There are some high round count (30k+) articles/threads around, I don't remember any gas tube failures in any of the properly built firearms.

^^^Spot on.