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.
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.
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/MI-Upper-Receiver-Rod-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-page/ar15-m16-barrel-nut-wrench
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?
7075T6 can be heated to 250 degrees for no more than a total time of 30 minutes without negatively impacting the heat treat.
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.
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.
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.
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.
Update: One hour of freezer time followed by heating with a torch, then using the scalloped wrench with a breaker bar has proven unsuccessful. I’ll wait a little while longer and see if there are any other ideas before cutting the nut off. Sending it out is likely to cost more than the upper ill likely destroy. Is there a need for these to be this tight? I have to assume that these are tighter than 80ft-lbs. Would it be unreasonable to put the impact wrench on the end of the brownells rod? I’m mostly joking.
I think your loosening torque is being lost in distorting the indexing pin notch around the indexing pin instead of actually loosening the barrel nut. If you had them, the clam shell vise blocks might make a big difference.
Is there a preferred brand of vice block? Best I could do at the moment is clamp the upper in the vice with wooden blocks between the takedown lugs and across the top rail.
People seem to like these ones. > https://www.btibrands.com/product/delta-series-ar-15-upper-vise-block-clamp/
I’ve been wanting to try these ones. > https://rguns.net/shop/r-guns-a3-receiver-vice-block/
Ordered… Now we wait…
Thanks for everything. Hopefully I’ll be back in a few days with good news.
The clam shell vise blocks aren’t super expensive, so it’s certainly worth the try… It just might work out.
No need to destroy the upper.
If you have a four or five inch vise and it is securely mounted either make or buy a set of barrel clamps.
Get some help to hold the armorers wrench securely onto the nut, use the breaker bar and slide a pipe over it to add extra leverage (a cheater bar - most of the time I use an old piece of chain link top rail) pull.
If that outruns the grip of your barrel clamps line them with some appropriate sized rubber hose and try again - you can generally buy 1/2 to 1 foot of appropriately sized hose at a hardware store.
Using the barrel clamps probably runs about the same risk of shearing the index pin as do the receiver blocks but applies less stress to the receiver.
If you cant get it loose and need to cut the barrel nut take a dremel and cut about half way through the nut. Try to loosen it, the nut may split or give enough to get it off. I’d start conservative and cut a bit more each time it doesn’t work, less chance of getting to the threads. Try to orient so the end of the ‘scalloped’ area of the wrench are on the ejection port side of the groove in the nut, not bridging the groove.
You can also cut more than one groove.
26 Inf,
He isn’t going to get anywhere new with barrel blocks, he’s already been using the Brownells barrel extension tool which accomplishes the same thing.
You are absolutely correct, I forgot that as I read through the thread, wondering why no one had mention barrel blocks. :rolleyes:
I have the knock off Geissele Reaction Rod from BOTACH, it has flats and is designed to be gripped in the vise as you use the armorer’s wrench to apply the torques. If the OP has been using the Brownell’s tool to apply torque while trying to hold the barrel nut into a vise mounted armorers wrench I could see some problems.
I would mount the Brownells tool in the vise (probably need to build or get vise blocks) and give that a shot.
(I’d guess that Brownell’s didn’t put flats or their barrel extension tool and wrote the instructions as they did to avoid conflict with Geissele)
The Brownells version has a 1/2" square socket in the end opposite the lugs. Placing a 1/2" socket wrench in that and then securing the round portion of the tool in the vise jaws, with the socket wrench up against the lower portion of the vise makes for a rather rigid setup, and the there is no way for the tool to rotate. The barrel is vertical in this orientation, but it could rather easily be placed horizontally. You can also secure the barrel wrench in the vise and use the 1/2 socket with a breaker bar. I have tried both ways and seem to get a better “grip” on things with the upper/rod/socket setup in the vise.