How can I safely loosen tight threads?
I'm getting ready for my first-ever FF handguard install (see https://www.m4carbine.net/showthread.php?t=104155 ). I'm reading a lot of accounts of broken uppers and other nightmares in getting the barrel nut off, as well as trouble in general with other tight threads such as with removing flash hiders.
I've got a receiver block, barrel-nut wrench, and barrel block coming in my Brownells order along with everything else for the FF install, so am hoping for the best. I'm still expecting difficulty though, based on that getting the FSB pins out last weekend was a major battle.
Can I assume that WD-40 is a first step toward loosening the threads? That's what I've always used on any non-gun related work.
Secondly, is heat from a propane torch advisable, and safe for all rifle components? Again, I'm just going on work-related experience here.
Are there any other considerations, other than just go-slow?
Lastly, once I hopefully get everything off and am ready to re-assemble, should I put anything on the threads to make it easier next time, or should they just be as clean and dry as possible?
I'm looking forward to this project making a better rifle, and not a smoldering pile of wreckage. Thanks for any help.