Gunsmithing Okay... Wtf? (Bent gas tube)

[SuperSneakySniper]

Update: I just got a new gas tube, this time a WMD one. It is bent JUST like the first one! I put them on a flat marble table and both of them are visibly bent... What the hell? Are all gas tubes bent? Or am i just getting unlucky? Does anyone have proof of a straight one?
It can't be the barrel or gas block fault becuase i can see the bend in the tube when i lay it flat on its side. Is the bend shallow enough to not cause any trouble? Does the little guide hole in the upper receiver set it straight when i assemble it? (I cant test that until my upper arrives).

For reference, original post:

Sup guys.
This may be a dumb question, but I've put together a couple AR gas blocks/tubes and I never had any that were bent to the left/right.
The one I currently have was bent a noticeable amount to the right (if looking out the barrel), so I bent it back to the left to straighten it out. It looks better now but it's not 100% straight. I can still see a slight bend in it.

For reference, the index pin thingy that lines up with the upper receiver (on the top of the barrel, the pin that indexes with the upper), the center of the gas tube floats over the right side of that pin, so it's not going down the center.

I would post a pic but photobucket has gone to crap for me i don't know what's up with it... If needed I can try to resize an image and post it through the site, but from what I've described, do I need a new gas tube? I don't want ANY added friction to the gas key when the gun cycles.
I would press it to a receiver and check for function, but my upper is being coated right now so I don't have any stripped uppers to test with.

Thanks,
-SSS

 

[padom]

Just order a new $15 gas tube. Simple fix

 

[prebancolt]

Agreed. Buy a new gas tube. IF you ever had an issue, you'd always wonder if the bent tube was causing/contributing to the problem. Easier to fix now than later.

 

[SuperSneakySniper]

Roger that, fair enough. Thanks guys!

 

[Waorani]

Yeah, they're cheap and easily replaced but unless kinked - save the old one, you'll use it at some point after some careful pressure to straighten.

 

[SuperSneakySniper]

Updated for new gas tube with same problem

 

[Ledzep]

Yeah they all have a bend to them because there's a radius difference from the bore center axis between where it plugs into the upper and where it plugs into the gas block. Should be 2 bends, actually.

 

[SuperSneakySniper]

Yeah they all have a bend to them because there's a radius difference from the bore center axis between where it plugs into the upper and where it plugs into the gas block. Should be 2 bends, actually.

Ty for the input, I do know that those bends (from bore to gas key/upper) are supposed to be there, the bend I'm talking about is a bend to the right. Like... If I am looking down the barrel (from shooter point of view), the end of the gas tube is noticeably sticking to the right side. Sorry if I didn't make that clear in my post.

 

[MarinePMI]

I think you might be over thinking this. If the tube is straight inside the receiver (i.e. not binding on the carrier key), there are no kinks in the tube, and it fits securely in the gas block, then it doesn't matter. Hence why we can use pig tail gas tubes...its basically an exhaust pipe. It can wind and bend all it wants, as long as the gas gets to the bolt carrier, and the bolt carrier key is not losing bolt velocity by hanging up on the gas tube.

 

[SuperSneakySniper]

I think you might be over thinking this. If the tube is straight inside the receiver (i.e. not binding on the carrier key), there are no kinks in the tube, and it fits securely in the gas block, then it doesn't matter. Hence why we can use pig tail gas tubes...its basically an exhaust pipe. It can wind and bend all it wants, as long as the gas gets to the bolt carrier, and the bolt carrier key is not losing bolt velocity by hanging up on the gas tube.

Right, im only concerned because the end of the gas tube (where the gas key is supposed to slide over) is bent to the right, and im not sure if it will go into battery. Unfortunately i cannot test it without my upper in hand. I think ill have to wait until my upper arrives, then i can tell for sure and put it all to rest. Ill update with my findings.

 

[Waorani]

the index pin thingy that lines up with the upper receiver (on the top of the barrel, the pin that indexes with the upper), the center of the gas tube floats over the right side of that pin, so it's not going down the center.

I missed how minimal this was before. That's a very, very slight bend and will totally disappear when tube goes through port on upper. In dozens of AR builds it's been common that gas tube has a slight right/left cant. I thought you were talking about an actual bend.

 

[sandwarrior]

Can you post a pic of the tube?

 

[SuperSneakySniper]

I missed how minimal this was before. That's a very, very slight bend and will totally disappear when tube goes through port on upper. In dozens of AR builds it's been common that gas tube has a slight right/left cant. I thought you were talking about an actual bend.

Ah! Okay thanks! In that case ill just wait for my upper to come back and install it rather than trying to return the tube. Ill update if it's still a problem. Hopefully youre right and I'm worrying about nothing

 

[scudzuki]

There's nothing wring with tweaking a gas tube slightly to better align the "spigot" with the gas key, and doing so will not affect longevity of the gas tube.
I've built at least 50 ARs and on a few of them, the gas tubes did not line up perfectly with gas key without a little tweaking.

 

[supercorndogs]

There's nothing wring with tweaking a gas tube slightly to better align the "spigot" with the gas key, and doing so will not affect longevity of the gas tube.
I've built at least 50 ARs and on a few of them, the gas tubes did not line up perfectly with gas key without a little tweaking.

In my opinion you should always tweak it. Making sure the gas tube slides smoothly into the key, in my experience, is a big factor in accuracy. I have wondered if heavier buffers and springs help is two fold. Not just increasing dwell time, but consistently stripping the round and closing the bolt to the same place. Could just be me being superstitious or something.