a year or two back, I bought a 12" 300BLK (CHF barrel, PSA quad rail, SQR(?)).  i am 99.9% sure it is this ONE.

I am looking to swap the handguard out and cannot get the barrel nut off.

there was no lock-tite/anything on the gas block screws, so I was encouraged that it would not be too hard.  But, there is SOMETHING on the barrel nut as it will NOT come off no matter what amount of torque I apply.  I don't want to break anything.  The nut has flat sections on it for using a standard wrench (i.e does not require proprietary tool).

Before I start heating it (in case it is rock-set) or soaking it (in case it is lock-tite), does anyone know?

thanks in advance.

well, there are threads where it has been beat to death

you can do it by the book, or you can do it the way everybody on youtube does it and have been doing it for a thousand years.....

I prefer to do it by the book......

yeah, i was hoping someone from PSA might tell me what I am dealing with as there are different methods.

should I not hold my breath?

My PSA was put on by a gorilla.

I sprayed some breakfree on the threads and let it sit over night to seep in.

Tossed the whole upper in the freezer for a few hours.

Clamped it securely in vise and hit just the barrel nut with a heat gun.

I was able to get it loose after a bit of struggle and help of a 2ft cheater bar.

A barrel nut with flat sides? New one on me but I haven't done that many....

it is a ROUND barrel nut, but has "flats" in it so you can use a regular wrench on it.  damn if a gorilla did not put it on like the other guy said.

It has a CHF 300BLK barrel and I really don't want to break the index pin or my bench vice or anything else.

I have the exact same barrel nut on my PSA upper and just removed it today. I placed the upper in a vice block and used a large adjustable wrench and a rubber mallet. An internal barrel support like a Geissele reaction rod is not a bad idea to ensure the barrel stays put. If you don't have one ask your LGS if you can borrow theirs (you may have to give them some collateral or a hold on your Visa while you are borrowing it).

Stubborn barrel nuts are generally torqued up to 70 ft/lbs so a rubber mallet is needed to strike the wrench to "shock" the nut loose. A few good whacks will do the trick. Just make sure the wrench is on securely and the vice is stationary.

It took me four whacks and the nut came unjammed and easily screwed off.

I hope this helps.

Thank you, I now have greater confidence in my ability to remove the very same barrel nut !

I have now tried heat gun, cheater bar, and almost broke my workbench trying to get this thing off.

 Can anyone confirm if it is lok-tite?  Or just a gorilla that torqued it way too tight?  I really do not want to break my barrel index pin or anything else

this is pissing me off.  Why the hell would they torque it so damn tight?

No Lock-Tite, it's just on by 70ish ft/lbs. I don't think any form of heating, freezing, or soaking in any kind of penetrating oil is going to solve your riddle.

Use an upper vice clamp, a Geissele reaction rod (or some form of internal barrel support) to stabilize along with a wrench and a rubber mallet to shock the nut loose.

You just need to overcome the torque of the nut.

IMHO, trying to use a steady pressure is just putting your upper and barrel at more risk of damage.

Tried heat and didn't have a good receiver block... did get the barrel nut off but also cracked my upper receiver. +1 on using a reaction rod and aerokroil the night before, or take it to a local gunsmith to remove for a couple of dollars...

The key is securing the upper and barrel prior to removing and/or tightening a barrel nut.

It's just good common sense to make sure stationary parts remain stationary before any torque is applied.

I hope this makes sense.

I got it finally.  Took me and another guy.  Geesh

thanks all for the help

Glad to hear.

I am sure this has been a great learning experience.