For ARs you have to have an FFL to sell lower, but as far as I can tell, pretty much anyone can assemble and sell uppers as long as they are not making or selling the lower assembly. Is this because the AR upper group by itself is not considered a firearm, but the lower receiver is considered the firearm for regulatory purposes?
What does the ATF define as a "firearm?" Is it the receiver? Meaning that you can make and sell as many magazines, barrels, triggers, stocks, etc (including in the case of the AR, assembling upper groups) as you want without being a licensed manufacturer or dealer as long as you aren't manufacturing and selling receivers?
What does the ATF define as a "firearm?" Is it the receiver? Meaning that you can make and sell as many magazines, barrels, triggers, stocks, etc (including in the case of the AR, assembling upper groups) as you want without being a licensed manufacturer or dealer as long as you aren't manufacturing and selling receivers?