So with all the information swamping the internet about SBR, I am overly confused and cannot find a direct answer in English from a reputable source.

I am in Michigan.

I understand that you can build an AR pistol using a lower that has never been registered as a rifle.
Then you have to register said lower as a pistol.

I can't find a straight answer on 80% lowers though. If you build a SBR/Pistol using an 80% lower, do you have to register it?
Or does it fall into the firearm manufactured for personal use category?

Do you have to register firearms at all in your jurisdiction? Or is buying one thru an FFL sufficient - and waives going to the local police with the gun to have it entered into their books?

If you don't have to have the gun inspected by your LEO's and recorded, you don't really have it registered. And there is the crux of the issue. An FFL only records a transaction required by law, that a completed gun, or in this case, a lower with serial number, is passing thru his business as legally required to transfer it to the owner.

That's about as much "registration" as goes on.

When you purchase an 80% lower, it's not a firearm, nor does it has a serial number to even note. It can be shipped directly to the owner's residence without passing thru an FFL - which is the entire point, as the cost isn't a major advantage. Blemished lowers are on the market for $39, most 80%'s I've seen are $80 and up with a jig to finish extra.

The attraction for some is the complete avoidance of any record that the lower is in the owner's possession. However, the closing of one vendor and confiscation of their sales records doesn't support that in a positive way. There are other methods that do ensure the lack of government oversight - like buying a lower thru a private seller.

Once the lower is finished and can readily accept a lower kit with trigger, it then becomes legally a firearm and the rules of selling one apply. Don't think that it means the rules that a major licensed producer apply, tho - the BATF is fairly clear on that. It's the large licensed makers who are required to serial number their product and sell it thru other licensed dealers or directly to the public. They have to follow the regulations, the individual citizen does not follow under those rules. What some buyers will insist, tho, is that you do, and provide a "number" to expedite their future transfer.

Registration, tho, no, not so much, not unless every person in your area has to march down to the police station and inform them of their purchase - or completion of a lower. Which I seriously doubt is required.

And, to add, it's better to build it first as a pistol. Don't attach a stock, go shoot it, then be happy. If you build it and use it as a pistol first -which many SBR users do - the firearm enjoys the distinction of not be a rifle first - because if it is, it then will always be a "rifle" to the BATF. But as a pistol, it can become a rifle and then back to a pistol, no regulations prevent it at the Federal level.

http://en.wikipedia.org/wiki/Gun_laws_in_Michigan

According to Wikipedia, which I wouldn't expect to be 100% on state firearm law, you'd need to register your pistol w/ your local city or county law enforcement officer - once you complete it.  Unless Michigan requires you to engrave a serial number, there's no Federal requirement that a self-built firearm have a serial number.  Make sure you record the encounter w/ the clerk & post it to You Tube.

"Where did you buy the pistol?"
"I made it."
"And what's the serial number?"
"There's no serial number."  

You might get a more comprehensive answer if you post this question in the MIchigan Hometown forum.

Federally, your 80% lower becomes a firearm like any other once it is completed and is thereafter subject to same federal laws and rulings as any other firearm. I suspect state of MI feels much the same.

Serial numbers are not required for this situation federally (unless made into NFA firearm), but no idea if MI law is different regarding that particular detail though.

- OS

Thanks for the replies so far.

I understand all the legalities with the 80% lower in its entirety. I actually used one for my recent build.
But after seeing all these pistol pictures, and having the building bug pretty bad, I want to venture down that road for my next build.

I did go the private route for my 80%. I figured having a record of something being shipped to me from a distributor kind of defeats one of the purposes. I am all for
liberties and such. And if the BATF says I can build my own and not have to serial it, then I say thank you and build it. No need for anyone to have my information on file.

I went with a polymer for my first build, just because I am a noob and wanted an easy method. With my tooling on hand it seemed like the best route.

For the pistol build though I would like to do an aluminum 80.

As for owning a pistol in Michigan, all I know is when I purchased the few I have I had to go to the CO Police office and apply for a permit to purchase.
I then took that to the dealer, they kept two copies and I kept the other two with their info on it. One is supposed to be filed back to the police and one in your possession.
The dealer then files one of theirs to the MI State police.

But I just don't understand how that would work if I build a pistol with an 80% with no serials.

I will give it a ask with that link provided, thanks!