I'm using the polymer receiver block from Brownells and locking everything in my vise.  I've already removed the front sight pin.  Using a barrel wrench I can get enough leverage to rip the plywood that the vise is bolted to, but it won't budge the barrel nut.  

I've heated the nut up and it still won't budge.  I heated the barrel nut, then wrapped the barrel in an iced cloth to cool it and max the temp difference, with no luck there either.

Right now my upper is sitting in the garage freezer, I'll try it again in a few hours.

What else can you think of short of cutting the ring and nut?

HELP!!!




PS-The search wasn't any help on this one...

You can try soaking it downn with penetration oil/lube and letting it set overnight, and then try heating it. I have had to cut a barrel nut off before.

Removed the front sight pin?? Don't quite understand what you mean. Have you removed the front sight and gas tube?? Sometimes a sharp rap on the wrench with a small hammer will 'shock' the nut loose.

It is sitting and soaking overnight (WD40).  If it won't come loose in the morning, I'll just cut it.  I've heard of a few other people having problems with a tight Bushmaster barrel, but I was hoping it wouldn't happen to me.

Even harsh language wouldn't move it, and I tried plenty!

Try an impact tool - the quick sharp strokes can succeed where long hard pulls will fail.

Most air impact guns will mount 1/2" sockets, so it should stick right in the barrel wrench.

Try positioning the upper in the vise so that you're pulling down on the wrench handle.  Put some kind of extension on the handle (like a pipe), and give it all your weight.

Thanks for the info, I'm finishing coffee, calling a friend, then hitting it again.

I'll post how well it does or doesn't end up.

Okay, it is all complete and it turned out fine.  The problem was that my workshop table had too much flex and the vise was giving.  Another example of the right tools for the right job.  A buddy came over and worked it with a cheater bar while I held the wrench in place on the barrel nut.

Simple job and it all turned out fine.  Now I need to resight it in and make sure the gas tube is lined up correctly with the BC.


rimfire50-  I never did figure out what you meant by removing the front sight.  I just popped the gas tube pin and pulled the tube.

 Why would I want to pull the entire front sight?

Guess I was thinking the reason you were pulling the ass'y was to install a floating handguard (using an integral barrel nut) or something which would require removal of the front sight anyway?? Glad you got it loose, be sure to lube it before you replace it. Didn't mean to infer you were equally ignorant, but I know of at least one guy who was trying to unscrew the barrel nut with the gas tube in place!

No problem, it was my first barrel swap and I thought I had missed something.  You had me going all through my military manuals wondering what I missed, and then rereading them again.  I did remember to lube it back up, it didn't look like Bushmaster had bothered to lube it from the factory.