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.