Help! Barrel nut goes 1/4 turn past the gas tube hole

Help! What do I do is my barrel nut goes 1/4 turn past the gas tube hole when finger tight? I'm installing a DPMS rifle length free float tube. --TIA

Did you lube the threads and tighten it three times, loosen off again and then come to tight? It should be torqued, but I've done both a bit looser and very tight. I'm thinking if you lube and it'll come to the next available hole. Use a locator pin so you can see where the hole lines up without having to poke your nose in there.

Finger tight means nothing. Torque it to spec a few times and back it off as Jim stated and go from there. The torque is 30 to 80 ft pounds. I take it to 60 and see where it is. 30 to 80 leaves an awful lot of wiggle room. The gas tube notch WILL line up in that range. Use moly lube or anti-seize on the threads as discussed in the other thread.

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Originally Posted by Bill Hollinger

The torque is 30 to 80 ft pounds

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Zactly. You'll be fine.

Thanks all. OK, here is what I did, then stopped to ask the experts here before I did something wrong. I am installing a DPMS rifle length free float tube. After removing the front sight base and the old barrel nut, I used moly on the threads and screwed on the new tube. It stopped with the gas tube slot at the 3 o'clock position. I was not sure if the torquing would allow it to rotate the needed 270 degrees. I'll torque it this morning.

I removed the FF tube. Cleaned and reapplied moly to the threads. Tightened, untightened then retorqued the tube four times. I can get the gas tub slot only to the six o'clock position. What am I doing wrong? Or, do I need some shims? **Note: this is a FF tube that has standard A2 handguards (no heat shields) so it looks like a normal issue A2 for CMP matches.

Can you send us a pic of the nut? It doesn't sound at all like the ones I've installed. If there's no place for the gas tube, how are you wrenching it in place? There should be serrations all the way around.

Is this the nut? The holes should be all round...


Attachment 54433

OK, I plead ignorance and a bit of stupidity. As my old college math professor would say - RTP (read the problem) when I would jump into a conclusion. The problem, when I looked closely at the various parts, is that the spring and the handguard retainer clip have a built in slot that must be aligned with the handguard retainer which in turn is rotated to match the barrel nut space between the teeth. This particular DPMS FF tube assembly (part FF-DCM) employs a barrel nut similar to a standard nut, but has a threaded portion which the FF tube with front swivel screws on. When the HG retainer, spring and clip are aligned, then it can be rotated to match the barrel nut. However, and the nut is tightened, the three parts do not move together, and must then be realigned to match the barrel nut so the gas tube will pass through. I did not realize this, initially. I know heve everythis aligned and the nut torques. Thanks again.

Once I realized how the parts went together, everything fell into place. Thanks again for your comments.

Great to hear that! Now, pictures or it never happened ;)