Thank you, CoRoMo and Sam1911 for both chiming in with your accurate summaries of the issues and lucid responses to tepin. I was afraid I was going to have to log in after work and write a diatribe to explain myself.
Ah, what the hell... why waste the chance to rant?
Let's start with some inarguable facts:
Fact #1: The ATF (and their representatives in the courts, the United States Assistant Attorneys) have the burden of proof in any criminal case. They must prove beyond a reasonable doubt all the elements of any offense, including offenses under the National Firearms Act.
Fact #2: The National Firearms Act defines what a rifle is, what a pistol is and what a short-barreled rifle is.
Fact #3: The ATF is a federal agency without the resources to check in on every gun owner and research the history of their firearms to check for their legality under obscure and arcane interpretations of the law.
So, with those facts established, what are we talking about? We're talking about making AR15 pistols and not accidentally running afoul of the National Firearms Act of 1934. We all know that if we want to make a legal short-barreled rifle, we can start with any firearm (rifle, pistol or "other"), file the proper application, receive the proper stamp, and then build a firearm that meets the statutory definition of a short-barreled rifle.
The potential problem for someone making an AR15 pistol is that while it is okay to make an "other" firearm into a pistol, it's not okay in all circumstances to make a rifle into a pistol. This is because part of the definition of short-barreled rifle in the NFA is "any weapon made from a rifle (whether by alteration, modification, or otherwise) if such weapon, as modified, has an overall length of less than twenty-six inches." So if you have a firearm that is a rifle, and you make it into a pistol less than twenty-six inches long, you've made a short-barreled rifle.
Ah, but not so fast! See, there was this United States Supreme Court case where the Thompson Contender company was selling kits that contained a receiver, a short barrel, a long barrel and a buttstock. There were warnings with the kits that you should not build a configuration with the buttstock and the short barrel without getting a tax stamp. Thompson's idea was that you could make either a pistol or a rifle and switch back and forth at will.
The ATF, though, said no way. They said that if you made the kit into a rifle, then any firearm you made it into after that was a "weapon made from a rifle with an overall length of less than twenty-six inches."
The US Supreme Court called hooey, and Thompson Contender won. For a while after that, the ATF took the position that the case ONLY protected Thompson's kits, and that the logic didn't apply to any other firearm.
This is known as the "once a rifle, always a rifle" doctrine.
In recent years, the ATF has backed off of this interpretation. They now say that as long as a receiver is made into a pistol FIRST, it can thereafter be made into a rifle, then turned back into a pistol without breaking the law. However, the ATF continues to hold that if the firearm begins its life as a rifle, then it cannot ever legally become a pistol.
Perhaps a little flow-chart would be helpful.
virgin receiver --> pistol OK!
virgin receiver --> rifle OK!
virgin receiver --> pistol ---> rifle OK!
virgin receiver --> rifle --> pistol NO WAY, JOSE!
virgin receiver --> pistol --> rifle --> pistol OK!
virgin receiver --> pistol --> rifle --> pistol --> rifle --> pistol OK!
virgin receiver --> rifle --> stripped receiver --> pistol NO WAY, JOSE!
Are you seeing the pattern? As long as it's made into a pistol first, you can swap back and forth as much as you want, forever. But if it's made into a rifle first, then you cannot ever make it into a pistol.
Now where people start to get more confused when they want to make an AR15 pistol is when they ask the question: But how do I know whether this hunk of metal in my hand is a virgin receiver? How do I know that it isn't somehow technically a "rifle" or a "pistol" already?
There are three cases we're concerned about, and they should be discussed separately.
First case: a stripped lower receiver bought from a dealer who bought it directly from the manufacturer.
This is EASY, but as we can see above, people want to make it hard. What defines the status of a stripped receiver? Well, what it looks like.
And this is the major point: it doesn't matter what the manufacturer's forms say and it doesn't matter what the dealer's forms say. You can't transform a stripped receiver into a rifle from a legal perspective just by writing it on a piece of paper any more than you can transform a stripped receiver into a turnip by writing it on a piece of paper. This is because (wait for it), the ATF must prove beyond a reasonable doubt that your firearm meets the criteria for an unregistered short-barreled rifle.
So they have to prove two things:
1) It's not registered.
2) It's a short barreled rifle because it meets the legal definition.
The legal definition is "any weapon made from a rifle (whether by alteration, modification, or otherwise) if such weapon, as modified, has an overall length of less than twenty-six inches." And to show that they've met that burden, they have to show it was made from a rifle. The legal definition of rifle is "a weapon designed or redesigned, made or remade, and intended to be fired from the shoulder and designed or redesigned and made or remade to use the energy of an explosive to fire only a single projectile through a rifled bore for each single pull of the trigger."
If it was never a weapon designed to be fired from the shoulder, (aka had a stock on it) and made to shoot a projectile through a rifled bore (aka had a barrel), then it was never a rifle and therefore cannot be a short-barreled rifle.
Even if the dealer incorrectly marked the 4473 as "rifle," the receiver wasn't a rifle if it didn't have a barrel and a stock.
So, if you bought a stripped receiver from a dealer who got it from a manufacturer, you can build it into a pistol. PERIOD. You don't have to get documentation from the manufacturer or even care what the dealer puts on the 4473. You know it never had a stock and barrel on it, so you're good to go.
(And as to tepin's point that it's good insurance to just contact the dealer and manufacturer to check: the problem is A) you're bothering people that are busy and have better things to do and you sound like a loony, and B) you have no guarantee that they didn't just tell you what you wanted to hear. Good thing it doesn't matter!)
Second case: a stripped receiver that you milled yourself from a piece of aluminum, from an 80% lower receiver, or glued together using sticks of bubble gum
This should go without saying, but perhaps it doesn't. It's legal to make your own firearms for your own use. As many as you want, whenever you want. (Let's not get into the legal gray area of when personal manufacturing becomes commercial manufacturing. You know whether you're truly building for your own use or for sale.)
If you made the receiver, you know it was never a rifle. So you're good to go.
Third case: a stripped receiver bought from a source that makes its provenance disputable
This is the "used" receiver. Maybe you got it from a buddy. Maybe you bought it at a gun show from a private individual. Maybe you bought it from a dealer who told you it was used. Maybe you found it at the bottom of a river. No matter where you got it, you have no way of knowing whether it was ever assembled into a functional firearm before it came into your hands.
Look, if you're a cautious, risk-adverse person by nature, then don't build this receiver into a pistol. Why? No good reason...
except that maybe it was once built into a rifle without being built as a pistol first. Go back to the flowcharts above. See that last example? That might have happened here and you'd have no way to ever know. If it was built as a rifle and then became a stripped receiver again and you build it into a pistol, then you're in violation of the National Firearms Act, according to the ATF's current interpretations.
But if YOU can't prove what the receiver may have been originally built into, how in the heck do you think the ATF is going to prove it? And let's not forget Fact #1. You don't have the burden of showing that it was a pistol first. The ATF has the burden of showing it wasn't. And let's not forget Fact #3. They don't have the energy to waste trying to figure it out because they don't care. Unless you're a white supremacist living in a walled compound, smuggling cigarettes and building illegal machine guns. And you know what? Even then, they don't care enough to do the research on the AR15 pistol. They're just gonna bust you for the other stuff.
You might well conclude, if you're an adventurous, care-free sort of a soul, that you simply have no risk of being prosecuted on the unlikely chance that the used stripped receiver you bought was once a rifle before it was ever a pistol and before you bought it in its current state. I say: go for it man, live life on the edge. Have some bacon for breakfast while you're at it.
Conclusion
So there you go. My rant on why people are worrying too much about making AR15 pistols from stripped lower receivers. And just to cover the other often-discussed points again:
1. You don't need to mark the lower with the words "pistol" or buy one that's marked that way. Markings don't make the gun a pistol. Its configuration makes it a pistol.
2. You don't need a dedicated pistol buffer tube. But they don't hurt. If you have a pistol buffer tube, there's never a question that you've got a pistol. You can also use a regular carbine or rifle length buffer tube. The ATF says it's okay. (Really, they do--the tech branch letters are out there.) But if you happen to have an extra buttstock laying around that can slip onto that non-pistol tube, and if you happen to have the ATF bust down your door, then you'll probably get into trouble. Proceed at your own risk, having being properly advised.
And, because this was a long rant on a legal topic, a short disclaimer before I sign off: I am a lawyer, but I am not your lawyer and this isn't legal advice and we don't have an attorney-client relationship. If you're really worried, go pay a lawyer that's extremely knowledgeable about the NFA to get the same information I just gave you for free. Then if he's wrong, you can sue him, not me.
Aaron
Sending an email too much trouble? Are you kidding? I sent an email to PSA on a stripped lower I bought and they answered within 3 hours. Its called customer service and the people I do business with believe in it... or they end up with a bad reputation and lose customers.
