Did I ruin something: AR15 barrel nut...

[Gdbyrd]

So I went to my dads house to torque my barrel down. I used the type of block where you pin the upper receiver into it, not the clam type.

Long story short, I'm not used to using a torque wrench. I read a tutorial online where you tighten, then loosen(doing this x3 to work the threads or something like that).

Anyway, when I torqued the barrel on I kept putting a little more weight at a time on the wrench and it never broke. When i went to loosen it to retighten, I couldn't get it to break free. It was ridiculously tight. I ended up having to tap it loose with a hammer.........

What's likely to have happened to it? Any damage??? The barrel nut teeth are all chewed up, but it's still functional. I can't find any barrel nuts in stock anywhere and ebay has them going for 60$ right now. Can I reuse this barrel nut and torque it to 30# once I have the chance to get a new(working) torque wrench?

Sucks this happened. This was the first upper I have built and it's really all my fault. Wish i had been paying more attention.

 

[Sam Cade]

A. Did you properly grease the threads?

B. The 30 lb spec is for a reason.

 

[Gdbyrd]

I did grease the threads. I had the torque wrench set to 30#, but again, do to my lack of familiarity of using one I didnt' know what to expect. The length of the wrench gave me a lot of leverage.

No duh on the 30#, lol. However I have seen torque specs from 30-70 lbs. I just have no clue how much torque I had on mine.... And what damage I could have done to the upper receiver/threads by possibly overtightening it.

 

[1911 guy]

Gdbyrd, I'll do you a favor if you need it. PM me your address and I'll send a spare barrel nut to you, you just have to promise to send me at least enough cash to cover the postage. I happen to have a leftover stock nut from doing a free float on a varmint barrel.

We gotta try to help each other out through this craziness until things calm down a bit.

The spec I have always used is 60 FtLbs twice, then final torque to minimum of 30 FtLbs.

 

[helotaxi]

and a maximum of 80 ft-lbs

You can apply an insane amount of torque to the barrel nut without damaging it provided the wrench doesn't slip. Be careful with the "pin in" upper receiver vise blocks since you can bend the front takedown lug torquing the barrel nut. That's where all the force is concentrated on the upper with those blocks and once it's tweaked, the upper is scrap.

 

[rcmodel]

I have seen torque specs from 30-70 lbs.

And somewhere in between there, one of the gas tube slots in the nut will line up exactly with the gas tube hole in the upper.

That is the only correct torque to use.

rc

 

[JustinJ]

As i understand the army and marines each have a different maximum torque.

Sometimes the barrel nut simply won't align properly within the torque range for the gas tube to pass through so the best thing to do is just get a different one although some will actually remove a little bit of metal from the receiver face.

The last barrel nut i removed was from my Colt 6720 and i was amazed at how tight that thing was. Must have been well over 80 ft lbs. I was putting on a Troy free float and the barrel nut it came with absolutely would not align below 80 so i just ordered a new one and it went on just fine at about 50, if i recall.