My next project is going to be an SBR 9mm AR with a suppressor. I want to send off for my stamps ASAP but I need some advice first.
I have a half dozen or so 5.56 lowers around the house and could use one of them with a mag block, but am I better off buying a 9mm lower for the build since it's already marked 9mm? Does it matter?
How would I register a 5.56 lower for a 9mm build if I decide to go that route? Do you just register it as multi-caliber?
Thanks in advance for any advice.
I have a half dozen or so 5.56 lowers around the house and could use one of them with a mag block, but am I better off buying a 9mm lower for the build since it's already marked 9mm? Does it matter?
How would I register a 5.56 lower for a 9mm build if I decide to go that route? Do you just register it as multi-caliber?
Thanks in advance for any advice.