It’s the Allen head screw and not the buffer tube that’s coming loose right? I’d blue loctite it, that should keep it in place and tight. I don’t know if I’d worry about the thread getting damaged but it could I guess, it would just be a pita to have to constantly disassemble the buffer tube to tighten the stock bolt. I haven’t ever had to tighten mine since I installed it, it’s been a couple years now and it’s rock solid. Nice looking shotgun by the way.