Barrel Nut-s

[FJ40 CRUZR]

Question: Barrel nut torque specs, i read 30-60lbs, what say you?

I purchased an upper BNIB and went to change the hand guard out, the barrel nut would not break loose, i mean i put a torque wrench on it and even at 90lbs it would not come free. WTF? do some manufactures really torque them that much? is that something you do? I was a little mystified as to why this was, i finally got a 5ft breaker bar and got it off.

When i reinstalled that barrel nut, i didn't get that crazy with it, maybe 40lbs. Should i leave it or give it a little more elbow?

[ElvenSoul]

I you sure it's 40lbs? If so it is in spec.

[FJ40 CRUZR]

I you sure it's 40lbs? If so it is in spec.

According to my cheap torque wrench.

[Alex$]

A torque wrench is not a breaker bar. Using it as such can destroy it, or more likely give you false readings. 90 foot pounds, or inch pounds?

[FJ40 CRUZR]

A torque wrench is not a breaker bar. Using it as such can destroy it, or more likely give you false readings. 90 foot pounds, or inch pounds?

Foot, I was not using it as a breaker bar. I tried using a breaker bar at first, when it would come loose I put my torque wrench on it to see where the ft lbs were by the click on the torque wrench. Once it clicked at 90 I knew I needed more persuasion, so i got the big bar out on the breaker bar.

[Alex$]

OK, obvious out of the way, almost. Any sign of thread locker or other "permanent" agent on threads?

If no, go with 40, it is within spec.

[fallfornoone]

yes, some manufacturers really tighten there nuts down and some really drive those A2 gas block pins in. BCM and DD were both pains.

[BeFrank]

It could that it was torqued at a different ambient temp than when you tried to take it apart.

[klewan]

I think if you get to 90 ftlbs and it won't move, get out the heat gun and your infrared temp gun. Up to about 400 on the barrel nut and then start torqueing. That way, if there is Loctite on it, you melted it. Way too easy to bend your upper being a gorilla with the cheater pipe on the wrench....

[Nathan Krynn]

Torque to 30 and then remove with another wrench. Do this 3 times and on the third line the gas tube slot up to the upper. This will make sure the nut has a good fit to the upper with the anodizing and proper fit.

You can go the extra mile and face it first to the rail as with anodize it will never be perfect. Not needed for everyday rifles but its a cool extra for accurate guns.

[ar15barrels]

It's pretty common to need a LOT more torque to remove a barrel nut than it was originally installed with.
This could be anything from a lack of lube causing the steel and anodizing to stick together to just crud in the thread junction.
I routinely run into barrel nuts that are way too tight to remove with just a DPMS claw holding the receiver.
I switch to a pair of PRI receiver blocks and clamp it all in the milling machine vise.
With the 2600lb mill to twist against and a 3fl long cheater bar, the offending barrel nuts come right off with no twisting of the receiver.

[klewan]

It's pretty common to need a LOT more torque to remove a barrel nut than it was originally installed with.
This could be anything from a lack of lube causing the steel and anodizing to stick together to just crud in the thread junction.
I routinely run into barrel nuts that are way too tight to remove with just a DPMS claw holding the receiver.
I switch to a pair of PRI receiver blocks and clamp it all in the milling machine vise.
With the 2600lb mill to twist against and a 3fl long cheater bar, the offending barrel nuts come right off with no twisting of the receiver.

I have a Bport, a vice on it; never thought to use it instead of the work bench vise. Thanks.

[ar15barrels]

I have a Bport, a vice on it; never thought to use it instead of the work bench vise. Thanks.

The bridgeport usually has the most solid mounted vise in a shop...