Seriously confused here.
From the article:
He told officials in June 2020 that he saw Awad manufacturing multiple firearms for sale. Awad would separately purchase AR lower receivers and AR upper receivers and assemble them at the shop, court records show.
“I know that an AR-15 is comprised of a lower receiver and upper receiver to make a fully functioning firearm,” the agent said in the complaint. “The main components of an AR-15 lower receiver are the body of the firearm, pistol grip, trigger mechanism, and butt stock of the firearm. The main components of an AR-upper receiver are the barrel, bolt assembly, and ejection port. Based on my training and experience, I am aware that the assembly of AR-style rifles from upper and lower receivers and other parts is considered manufacturing firearms.”
You stated above: "Receiver to rifle is manufacturing and requires marking"
**Please note that I'm addressing what are now somewhat historical conditions which are affected by the ATF's latest letter with reference to 80% kits**
I've purchased both 80% and marked lowers.
I've completed an 80% lower, assembled it and mated it with an upper. It's a "privately manufactured firearm" because the receiver wasn't completed when I started with it - it wasn't a firearm and when I was done, it was. But the upper has nothing to do with the transformation of the 80% lower to a "firearm", it's the completion of the pocket, the trigger slot and the horizontal holes for pins and safety. It required no marking because it was a "privately manufactured firearm" for my own use.
The marked lower required a 4473 and transfer through an FFL because it's a "firearm". When I purchased it, it was a "firearm". Finishing it and attaching an upper didn't change its definition or status.
So, let's look at the shop owner. I didn't see anything about 80% or "unmarked" lowers. If I read the article correctly, (and I quoted it above), he purchased marked lowers (which would have had to go through his bound book), perhaps installed lower parts kits, (the article isn't clear there), and attached uppers. The lowers were already defined as firearms, how does attaching an upper change anything?
I honestly don't see how that's "manufacturing". Can you "explain like I'm five"?
And - remember - this happened in Michigan - not Massachusetts. The lower is the firearm.
My response is purely federal law based and has nothing to do with any state laws or definitions. It also has nothing to do with the current 80% receivers, receiver kits, etc. This is all very basic and clear and not muddled by current events or political crap.
Federally we have a taxonomy with Firearm covering everything. Firearms can be different types with the obvious ones being rifle and pistol. If you decompose a rifle you usually have an object that is still a firearm called a receiver. A pistol maybe be made from a frame or receiver. The key concept here is that if you have a functioning rifle or pistol (or anything else) and decompose it, there is always some basic element that is the firearm until you decompose too far.
So if you are holding a receiver which is a firearm and marked, serialized, etc, you have a federally regulated item. Let’s say for this discussion it is Anderson AM15 stripper ar15 lower. If you take this and complete the lower by putting in a LPK and buffer and stock you still have a receiver and therefore what you have done is “gunsmithing”. The object has not changed state as it was a receiver and still is a receiver.
Now you attach a complete upper. The object you are holding is now a rifle. This is a change in taxonomy from a receiver to a rifle. This constitutes manufacturing. With the exception of manufacturing that is decomposing, you must mark the item when manufacturing. This is a FFL requirement we are talking about. Any manufacture must mark what they make. So you would keep all the markings you can but the FFL must add business name and business city and state. They must also record this manufacturing in their bound book.
If you turn a rifle into a receiver, this too is manufacturing. It must be recorded in your bound book. Because you are decomposing an existing object, there are no marking requirements as long as the resulting object is properly marked.
All manufacturing requires a proper FFL, an 07 in this case.
As a private party you have no requirements to mark or record what you make. So when you put an upper on a lower while it constitutes manufacturing, there are no federal laws that require marking, licenses, etc UNLESS you are doing it for profit. Private manufacturing for personal use is fine. Manufacturing for profit or for someone else even if not for profit requires a license.
You can help your friend build an AR. You can turn the stripped lower into a complete lower. You can build a complete upper. You cannot put an upper on a lower for someone else. Sure, this is very unlikely to get caught or cared about, but it constitutes manufacturing and you cannot do this for someone else without a license.