Gas Tube Tightness

[lumbergh]

While I am pretty sure that the gas tube, where it attaches at the receiver end, should be tight, I am not sure how tight it needs to be.

The new to me FAL was not cycling properly at range with SA surplus. At home, while cleaning (was disassembled at time), I noticed that gas tube nut was not tight.

I tightened it back up, but not with the special FAL wrench (ie not the tool DSA sells).

Is this a prime culprit for the failure to cycle?

It would not cycle even with gas fully closed.

TIA-

Lumbergh

[jim1of6]

Chris,

It's the other end at the gas block where gas tubes tend to add to the gas leakage.

Remove the retaining pin and tube. Sand, evenly, the end of the gas tube,checking often until you achieve a tight fit and have the retaining pin align. This has helped me in the past stop some gas leakage.

Jim

[Radio]

You make-a no sense, Señor.

The end of the gas tube where it joins the receiver is a SLIP FIT. Doesn't fasten to anything, it just sits there in the gas tube nut. Furthermore there is no gas pressure there at all. If I understood you correctly, and remember I'm getting old, you're concentrating at the wrong end completely.

The end of the gas tube where it joins the gas block IS where it's fastened... screwed into the block. That said, IT IS A LOOSE FIT. Proper installation is to screw it in until it bottoms, then back it off enough to properly time it at 12:00... the gas tube pin clearance slot is at the bottom, the longitudinal slot is clocked straight up, and the gas pressure relief vents are timed at 4:00 and 8:00. When you take all this into consideration and look at the blinkin' gas tube it all becomes immediately obvious.

Now, you DO want a good fit of the gas tube threads into the gas block. A fast way to check this is to wrap the threads with teflon tape. This is a very temporary test as the tape will soon blast out all over creation, but for a few rounds you'll find whether you have a vastly improved gas seal or not. One way to fix it (IF necessary) is to file a thread off the end of the tube (in other words grind the tube a bit shorter) so that you can get more of the fatter portion of the tube into the gas block. Remember that ultimately you still have to time the thing at 12:00. If this didn't work I might be so bold as to take off a second thread, but if THAT didn't work I'd just pick up a different (or new) gas tube.

Of course also make sure that the gas plug isn't the source of your troubles, that the gas regulator isn't opened too far, that the piston and bolt/carrier aren't binding, that the magazine isn't contributing to the problem, and that the recoil springs aren't getting into hydrostatic lock from too much oil.

--Radio

[ce]

What Radio meant, by the gas plug being your problem, is the gas plug has two settings, gas, or no gas.

The plug has either an A, or a groove, or both, on the gas setting.

It has a G, or not, on the no gas setting.

Make sure the A, or the groove, is on top.

What else does Radio mean?

That's for me to know, and for you to find out.

[Radio]

I shouldn't even be here. If we need to talk about blowing out gas, that stoopidfellow Hugh would be the proper authority. Very gas. Very gas, indeed.

[lumbergh]

Thanks for your input(s).

I have it worked out.

"I just fixed the glitch."

Lumbergh

[jim1of6]

Chris,

We knew you could do it!

Enjoy the G1 and let her out of the safe sometime.

Jim

[gunnut1]

The gas nut on the receiver end should be tight. The gas tube it self should be loose as Radio described.


I think ce has been snorting his sandals again! And he forgot about the transverse axial side also.

[BUFF]

Gas tube tightness...

Ya know, there's gotta be a joke here about DABTL and his fascination with male homosexuality, but... must... keep... Gunsmithin'... pure...