Is this a problem? Gas tube is touching the barrel nut on a build. PICS Added. - Page 1

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Is this a problem? Gas tube is touching the barrel nut on a build. PICS Added.

Ronnoc

Valhalla Calls

Joined Apr 2005
Posts 13134
EE 100% (19)

MO, USA

Posted: 8/16/2024 11:48:42 PM EST

[Last Edit: Ronnoc]

Built an 11.5 upper using a Geissele upper receiver, Mk14 Rail, 11.5 BA Hanson CL CHF barrel with pinned gas block, and a BRT EZTune gas tube. I had to really work the gas tube into the receiver, kind has a bell-shaped end and did not want to go easily through the gas tube hole. The the gas tube took a bit of effort to work it into the gas block and had to lightly tap it some as it was binding on the barrel nut. The gas tube went in, but were the bend in the tube is it rests/touches the Geissele barrel nut.

I put a CH/BCG in and they will cycle on pulling them manually, haven't tried firing the gun yet. At first it seemed to bind a bit but now moves freely. CH is a G Airborne and the BCG is NiB I had laying around, don't know brand, got it years ago from PK Firearms.

Wanting to see if the gas tube lightly touching the barrel nut is an issue and how much of the rest is normal/experienced by others. I have done 4-5 other builds previously and don't recall ever experiencing this. Don't have pics right now, did the build a week ago and no time to get out yet.

Thanks!!

Lo there do I see the line of my people, back to the beginning. Lo, they do call to me, they bid me take my place among them, in the halls of Valhalla, where the brave may live forever.

s4s4u Joined Sep 2007 Posts 11239 EE 100% (54) MN, USA	Posted: 8/17/2024 12:06:19 AM EST [Last Edit: s4s4u] [#1] I've never had such problems with a gas tube. Gonna have to see a pic. 1st time with that combo?

Ronnoc Valhalla Calls Joined Apr 2005 Posts 13135 EE 100% (19) MO, USA	Posted: 8/17/2024 12:21:00 AM EST [#2] Quote History Originally Posted By s4s4u: I've never had such problems with a gas tube. Gonna have to see a pic. 1st time with that combo? View Quote Yep, first time. I will have to take the rail off and take some pics tomorrow.
	Lo there do I see the line of my people, back to the beginning. Lo, they do call to me, they bid me take my place among them, in the halls of Valhalla, where the brave may live forever.

Ronnoc Valhalla Calls Joined Apr 2005 Posts 13136 EE 100% (19) MO, USA	Posted: 8/17/2024 12:49:38 AM EST [Last Edit: Ronnoc] [#3] I have a factory G 11.5 SD upper and looking through the rail it too looks like it's resting on the barrel nut. This is my build below. Attached File Attached File Attached File
	Lo there do I see the line of my people, back to the beginning. Lo, they do call to me, they bid me take my place among them, in the halls of Valhalla, where the brave may live forever.

OG1 Land of the once free & the home of the narrative. Joined Jan 2012 Posts 26512 EE 100% (201) AL, USA	Posted: 8/17/2024 4:55:25 AM EST [#4] It hurts nothing. All that matters is the end going into the bcg is not binding.
	"Whoever makes himself great will be made humble. Whoever makes himself humble will be made great." -Jesus "if it can be destroyed by the truth, it deserves to be destroyed by the truth" - Linus from Charlie Brown

TNRonin Your favorite member Joined Aug 2001 Posts 4295 EE 100% (45) TN, USA	Posted: 8/17/2024 5:12:02 AM EST [#5] Bending the tube to clear the nut if it bothers you doesn't hurt anything. I've seen it done.
	Shoot straight and tell the truth!

Jmo371 Member Joined Oct 2013 Posts 14267 EE 100% (43) NH, USA	Posted: 8/17/2024 7:17:22 AM EST [#6] its fine

MJ11B4P Joined Mar 2018 Posts 3852 EE 100% (124) SC, USA	Posted: 8/17/2024 8:01:57 AM EST [#7] Normal for that barrel nut and doesn’t affect function. Confirm no binding with gas key like any other setup.

triode Member Joined Mar 2010 Posts 2070 EE 100% (7) USA	Posted: 8/17/2024 8:09:06 AM EST [#8] Try a different gas tube to see if it has the same issue.

Switchback_Arms Joined Apr 2008 Posts 6358 EE 100% (22) USA	Posted: 8/17/2024 8:20:36 AM EST [#9] Looks good to me

Ronnoc Valhalla Calls Joined Apr 2005 Posts 13137 EE 100% (19) MO, USA	Posted: 8/17/2024 9:07:25 AM EST [Last Edit: Ronnoc] [#10] Thanks! Was wondering if part of it is the longer barrel nut on Geissele rails. No binding on the gas key.
	Lo there do I see the line of my people, back to the beginning. Lo, they do call to me, they bid me take my place among them, in the halls of Valhalla, where the brave may live forever.

s4s4u Joined Sep 2007 Posts 11241 EE 100% (54) MN, USA	Posted: 8/17/2024 10:18:45 AM EST [#11] Quote History Originally Posted By TNRonin: Bending the tube to clear the nut if it bothers you doesn't hurt anything. I've seen it done. View Quote I would consider doing this, if the gas tube isn't entering the carrier key smoothly. Otherwise it shouldn't affect function or accuracy.

TGWLDR GUN WHORE Joined Dec 2014 Posts 50869 EE 100% (449) IA, USA	Posted: 8/17/2024 10:56:09 AM EST [#12] They're all like that with the G barrel nuts, IME. Non issue.
	Can't never could 'til try came along. "All welchers should be removed from the EE".-Aimless R.I.P. to the EE

Ronnoc Valhalla Calls Joined Apr 2005 Posts 13139 EE 100% (19) MO, USA	Posted: 8/17/2024 2:12:38 PM EST [#13] Well, I certainly appreciate the good news and input!
	Lo there do I see the line of my people, back to the beginning. Lo, they do call to me, they bid me take my place among them, in the halls of Valhalla, where the brave may live forever.

kychas Joined Dec 2001 Posts 3254 EE 100% (1) KY, USA	Posted: 8/18/2024 6:50:30 AM EST [#14] Move a stripped bolt carrier slowly in and out and see if the gas tube is moved in any way for the gas tube to seat in the bolt carrier. It should not have much in the way of pressure needed to seat the gas tube into the hole If a little adjustment is needed you can gently adjust it

bfoosh06

Happy to be a Member

Joined Sep 2008
Posts 15196
EE 0% (0)

NT, USA

Posted: 8/19/2024 10:27:17 PM EST

[Last Edit: bfoosh06] [#15]

@Ronnoc

Accuracy wise... ( I know 11.5" ... ) the binding gas tube won't help precision grouping... including "separate" grouping.. IE 2 touching there and 3 touching over there, in a 5rd group..

https://www.snipershide.com/shooting/threads/ar-gas-tube-free-float-how-critical.71491/

And from here... https://bulletin.accurateshooter.com/2015/05/what-makes-an-ar-accurate-whitley-offers-answers/

9. A gas tube that runs freely through the barrel nut and through the front of the upper receiver and through the gas key in the carrier is not impinged by any of them so that it does not load the carrier in a stressed orientation, nor is it bound up so that when the gas tube pressures up it immediately wants to transmit more force and impulse to the barrel than would normally occur. We spend a lot of time sometimes taking the gas block with gas tube on and off "new build" uppers and "tweaking" gas tubes to get that best (and most gas tubes need a little "tweaking" to get them right - factory tubes go in and they work but they are typically not optimum without hand fitting).

And FWIW... and you may not want to hear this given your choice of the BRT EZTune gas tube ... but an SLR .750 Adj. GB ( probably other brands like the SLR as well ) "presents" the gas tube ( out the shoulder end ) .0091" higher then a typical BCM GB.

That might be "just enough" clearance over the barrel nut to allow your gas tube "free and easy" interface with the gas key, etc.
Also... this appears to be a common issue with longer then USGI barrel nuts. Geissele included.

Just my 2 cents.
At the very least, the gas tube and gas key will wear "faster" at that contact point. How much faster, I don't know, but I would be sure to keep it lubed there.

Myself... I would at least attempt to gently bend the gas tube to fit better and more freely.

OOPs... just make sure your choice in a higher Adj. GB clears your handguard with as much room as possible.... otherwise you'll have another set of accuracy robbing issues.

*Hold on to your AR-15s. Their magic must be very powerful, or they wouldn’t want them.*
JAFOM.... Just another fat old man.

________________________________

TOGC,IADC

bfoosh06 Happy to be a Member Joined Sep 2008 Posts 15197 EE 0% (0) NT, USA	Posted: 8/19/2024 11:00:12 PM EST [#16] Another article concerning gas tube contact... From Joe Carlos, a true AR guru. https://www.thefreelibrary.com/Gas+Tube+Alignment%2C+Revisited%3A+The+never-ending+saga+continues....-a0540679188
	Hold on to your AR-15s. Their magic must be very powerful, or they wouldn’t want them. JAFOM.... Just another fat old man. ________________________________ TOGC,IADC

bfoosh06 Happy to be a Member Joined Sep 2008 Posts 15198 EE 0% (0) NT, USA	Posted: 8/20/2024 12:32:38 AM EST [Last Edit: bfoosh06] [#17] And... Ironically, I just saw this while trying to ID a GB. Available in .750" , and .875" https://faxonfirearms.com/faxon-3-screw-ar-10-height-750-gas-block/
	Hold on to your AR-15s. Their magic must be very powerful, or they wouldn’t want them. JAFOM.... Just another fat old man. ________________________________ TOGC,IADC

Is this a problem? Gas tube is touching the barrel nut on a build. PICS Added.

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