Anangrypasta
Master
Hey guys, know this has been discussed.... but I just got my first AR lower ever and I want my AR in an eccentric/unused cartridge. I decided on 9x39. I can only find uppers at 12.5", and no barrels, so I would need an extension on my rifle lower. Do you have to weld/pin the extension? Is that something I can do assuming I have the ability, or do I need to go somewhere to have it done for legal reasons?