Barrel Nut Removal Tips?

[medicman816]

I've searched and can't seem to find an answer. I have a BCM factory upper that I would like to remove the GI barrel nut from in order to install an aftermarket rail. I have the Brownells brand barrel extension tool and a GI armorers wrench, have applied penetrating oil and heat, and can not seem to get this to budge. I've put most of my near 200# gorilla strength behind it and still a no-go. Is there a trick to this? What tricks have worked in the past? At what point does one just move on to the dreaded dremil tool for a more violent removal? Thanks in advance.

[Zane1844]

The BCM barrel nuts are torqued on by Zeus himself.

I used this wrench in the link and applied slow even pressure then it finally broke free.

I was using the GI armors wrench too, but kept breaking teeth off of the barrel nut. This wrench grips multiple points all the way around and really helps.

https://www.brownells.com/gunsmith-t...prod27412.aspx

[556Cliff]

There is a good chance that you are going to shear the indexing pin and damage the indexing pin notch in the upper receiver using the Brownells barrel extension tool to remove a stuck barrel nut.

Put your barreled upper in the freezer for an hour, then take it out and heat up just the barrel nut with a torch, then put your upper in the vise in a set of clam shell upper receiver vise blocks.

Stick this in the upper/barrel extension for added support. > https://www.midwestindustriesinc.com...d-p/mi-urr.htm

Then attempt loosening with a good quality barrel nut wrench... I prefer this one, but the one from PRI is good too. > https://www.2uniquellc.com/product-p...rel-nut-wrench

[medicman816]

Thanks for the help so far...

Im noticing a white substance around the threads, which I would hope is anti-seize. Im going to try the differential cooling now. Had it up over 350 with the heat gun without success. Is there a theoretical max heat?

[MistWolf]

7075T6 can be heated to 250 degrees for no more than a total time of 30 minutes without negatively impacting the heat treat.

[556Cliff]

I think BCM used to use a white lithium type grease on the upper receiver threads, though I'm not sure if they still use the same stuff anymore.

It might have taken to long to heat up with the heat gun, the aluminum upper will react faster to temperature change than the steel barrel nut will.

[MistWolf]

Use the scalloped side of the barrel nut wrench, not the side with pins. The scallops will engage more teeth and spread the stress over a larger area, reducing the chance of smearing our breaking the teeth.

[556Cliff]

Use the scalloped side of the barrel nut wrench, not the side with pins. The scallops will engage more teeth and spread the stress over a larger area, reducing the chance of smearing our breaking the teeth.

I don't think he has a wrench like that.

[medicman816]

The wrench has the scallops on one side and 3 pins on the other. I've been using the scalloped side. I hadn't really thought about the aluminum being heat treated and iI'm glad i asked. I know its off topic but I'm curious how it holds up to full auto fire (not this one, uppers in general) and stays under 250 degrees.

[joedirt199]

If you have a breaker bar to put in the AR wrench that helps. I use nylon covers made to go in a vice I got off ebay. The bottom one has holes and cross pins for the upper/lower joining pin holes. Top is groved to go over the flat top rail. It can be clamped down pretty tight and helps with those stubornly tight barrel nuts.