barrel nut issues

[napa valley sniper]

hey guys, im having a issue with an old m&p sport barrel nut. i cant for the life of me get it to budge. i have a upper vise block and an armors wrench but this thing is on there good. im currently soaking it in kroil overnight and i will try again tomorrow. ive heard things like put it in the freezer or heat it with a torch or heat gun. im looking for someone who has had this issue before and what did you do to get it off. Im thinking the amount of torque i put on the nut was enough to get it off but dont want to ruin the upper. any advice would be greatly apperciated

[ar15barrels]

Heat and cold saturation don't really work on an assembly because the whole assembly heats or cools and you don't get any differential.
It's the differential that makes heat/cold work.

What you need is a better way to hold the receiver.
I use PRI's aluminum blocks on the rail and the bottom of the upper and I clamp that whole setup in the milling machine vise on the table of the 2800lb milling machine.
Then I put a 4ft cheater bar on my wrench.



That setup removes ALL barrel nuts.

Your reciever block and bench vise are likely not strong enough to do that job without damage to the reciever.

[freonr22]

About how many ft/lbs does it take to remove, in your worst case scenarios?

[ar15barrels]

About how many ft/lbs does it take to remove, in your worst case scenarios?

Probably around 150ft-lbs.
Lack of proper grease on the threads lets the barrel nut lock to the anodizing and that means it takes FAR more torque to get it apart than it was put together with.

Going much beyond 60 ft-lbs while holding the reciever from only the bottom can be fatal to receivers.
Here is a factory colt reciever that split while trying to remove the colt installed barrel nut with only the bottom of the reciever held in a reciever block.

[kendog4570]

Probably around 150ft-lbs.
Lack of proper grease on the threads lets the barrel nut lock to the anodizing and that means it takes FAR more torque to get it apart than it was put together with.

Going much beyond 60 ft-lbs while holding the reciever from only the bottom can be fatal to receivers.
Here is a factory colt reciever that split while trying to remove the colt installed barrel nut with only the bottom of the reciever held in a reciever block.

Any good gunsmith worth his salt should be able to fix that in no time, at minimal cost. Piece of cake...

[SVT-40]

Any good gunsmith worth his salt should be able to fix that in no time, at minimal cost. Piece of cake...

J B weld!! And forget it!!

[kendog4570]

J B weld!! And forget it!!

All ya gotta do is...

[napa valley sniper]

AR 15 you were right on point. I first of all got a different upper vise block, (wheeler with the plastic BCG/gas tube combo insert). I also used a couple of scrap pieces of iron wood to brace the upper vise block. What i did different about torquing was instead of holding the wrench straight out horizontally at the 9 o'clock position and wrenching from there i put the wrench almost at a 7 o'clock position and wrenched it and it slid right off. Maybe the flexing in the wood that my vise was bolted to was causing less torque on the barrel nut. I guess the kroil oil could of helped as well. More vise support is definitely a must. Thank you for your knowledge guys i always appreciate it. Free float hand guard is installed and looking good.

[ar15barrels]

All ya gotta do is...

Exactly.