Gunsmithing bottoming out gas tube on barrel nut?

CST

Sergeant
Full Member
Minuteman
Dec 31, 2002
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I have a AR10 and installing a barrel with the DD free float 12"....the problem is that the barrel nut, while very thin, is not thin enough when the gas block and tube is installed....causing the gas tube to bottom out on the barrel nut and it does not "float" freely... THe bolt carrier still seems to move in all the way... Will there be accuracy problems in this situation?
 
Re: bottoming out gas tube on barrel nut?

The tube needs to float. I'm not familiar with the AR10 size DD rail, but the Troy DPMS LR rail has to have a notch filed in the rib on the nut. Is it just touching a rib on the nut or is the whole nut oversize? If it is just a rib, take a small round file and cut a clearance notch in the rib on the nut where it's touching.

If the whole nut is too big, I'd call DD, as you may have the wrong nut.
 
Re: bottoming out gas tube on barrel nut?

i thought they had to float as well..I have seen guns with nonfreefloated plastic hanguards that do not free float the tube becuase of the barrel but is to tight around the tube...doestn effect anything ...dont know about accuracy though...

I call Daniel Defence, Rainierarms etc...no one can give me straight answer....
 
Re: bottoming out gas tube on barrel nut?

I know Im new but if I can possibly help and if I may offer up some advise.I have free floated a Stag Ar-15 and a Rock River and own a Spikes Tactical M-4 1/7 twist DD barrel with a free float using a Troy Industries F/F Quad Rail. This is one of my work rifles. Does the bolt close all the way with the gas tube inserted though the barrel o.e.m. nut? Check to make sure, you know the problems that could arise from the bolt carrier gas key covering up too much of the gas tube and not allowing the bolt to close all the way. One question is did you unscrew the barrel o.e.m. nut and if so did you tighten it up to specs, you have to be carefull not to overtighten because the barrel index pin might over turn in the u shaped notch in you receiver, then you end up with an over indexed barrell. You could allways try buying another gas tube from an online store, they dont cost much and see if that works. Also when you drove the pin into the gas block thought the tube, was the tube placed in the correct angle to fit freely into the upper rec.? Out of the 3 M-4ergy's lol I have done the gas tube was able to move freely. Maybe it was some how bent or the tube was installed in the gas block at the wrong angle. I hope this may help
Respectfully Submitted by the FNG.
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