In the comments to Part 2, Sigivald says:
Ian: My impression of the ATF's interpretations of the law suggest that "if it was ever a rifle FIRST", it's a rifle forever for their purposes. (Same thing with a long barreled "normal" shotgun vs. AOW shotgun, which is why people going for an AOW rather than SBS buy factory-pistol-grip shotguns.) And thus despite not having a stock anymore it'd still be a "short barreled rifle" when converted to what any sane human being would call a "pistol".
That would be my impression as well, albeit via second- and third-hand osmosis and news of the occasional prosecution; and is one way to read the relevant statute, if the legal category of Handgun can overlap with the legal category of Short-Barreled-Rifle
Title18, U.S. Code, Title I, Section 921(a)(3)
(7) The term "rifle" means 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.
(8)The term "short-barreled rifle" means a rifle having one or more barrels less than sixteen inches in length and 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
(29)The term "handgun" means a firearm which has a short stock and is designed to be held and fired by the use of a single hand.
Title II, Sec 5845
(e) Any other weapon.:The term "any other weapon" means any weapon or device capable of being concealed on the person from which a shot can be discharged through the energy of an explosive, a pistol or revolver having a barrel with a smooth bore designed or redesigned to fire a fixed shotgun shell, weapons with combination shotgun and rifle barrels 12 inches or more, less than 18 inches in length, from which only a single discharge can be made from either barrel without manual reloading, and shall include any such weapon which may be readily restored to fire.Such term shall not include a pistol or a revolver having a rifled bore, or rifled bores, or weapons designed, made, or intended to be fired from the shoulder and not capable of firing fixed ammunition.
But, now comes the exciting part of tonight’s show. Do not try this at home without consulting a competent firearms lawyer, preferably one who has won multiple cases before the Supreme Court of the United States.
Take one (1) 1911-pattern-based .45acp carbine constructed from: a 1911-pattern frame that has never been assembled as part of a pistol, and a MechTech CCU for 1911 in .45acp. This is clearly and legally a rifle, both by common understanding and that of the ATF. It is not a Short-Barreled-Rifle because the barrel is more than 16” and the overall length is over 26”. Nor is it a handgun, as it does not have a short stock nor is it designed to be held and fired by the use of a single hand. It is not Any Other Weapon, either as it cannot be concealed on the person. It is a rifle by the above definition, however
Take one (1) 1911-pattern .45acp handgun constructed from: an identical frame to the example above, and a slide assembly designed and manufactured as the slide assembly for a 1911-pattern pistol that does not have any serial numbers that match the frame. This is clearly and legally a handgun, both by common understanding and that of the ATF. It is not a rifle as it is not intended to be fired from the shoulder. It is not a Short-Barreled-Rifle, as it is not made from a rifle. It is not Any Other Weapon, as it is a “pistol … having a rifled bored.” It is a handgun by the above definition, however.
Take two (2) kits to allow the conversion of 1911-pattern firearms from .45acp to .22lr. These are not firearms by law or custom, and therefore not any species of Rifle or Handgun or Any Other Weapon.
Detach the 1911-pattern frames from their respective upper receivers/slide assemblies. Place them on your workbench next to the conversion kits. Call your lawyer and make sure your legal defense fund is adequately funded. Ask my family to take the pets to your parents’ place for the weekend. Wait for them to get clear.
Attach the frames and the conversion kits. Contact the ATF and ask them which one is an unregistered Short-Barreled-Rifle. Place all the components into a gun safe, and step out onto the porch to await the Long Arm of the Law. Keep your hands in view and make no sudden moves.
I’ve perhaps exaggerated the physical danger to your person in this hypothetical; but I think I made my point. Some of the curlicues above regarding the specifics of each starting firearm are done to prevent identification of which frame started as a handgun and which as a rifle. Likewise, I’ve chosen 1911-pattern frames as the start as they can be sourced anywhere and can even be personally manufactured – it’d be harder to try and claim that a Glock frame is anything but a handgun frame, and would be much more difficult both physically and legally to personally manufacture.
Prior to Heller and the 111th Congress, this would have been a politically- and legally-risky move. Nobody knew if there was a right to personal possession of a handgun, and Congress could choose to wipe out the “handgun” exemption to Any Other Weapon. Heller proved that there is an individual right to possess an operable firearm, particularly a handgun, in the home for self-defense. That’s the core finding. And the 111th Congress showed that a Democratically-dominated Congress would still vote to allow firearms in National Parks and come within one vote in the Senate to force permit reciprocity down the throats of the States.
This leaves the ATF in a bind. On the one hand, they can ignore my hypothetical above. One guy with a handgun that, in a certain light, looks a bit like a SBR if you squint real hard, isn’t much of a threat to their regulatory scheme ,by himself. Until he tells his friends, and posts on the internet, and his friends tell their friends, &c… And the ATF, institutionally, prefers to bring that certain lightbulb with them, and squint at it really hard. And this case will yank the rug out from under SBR; because the next case won’t be 1911-pattern frames, it’ll be AR-15 receivers. And once you’ve shown that there’s no difference between an AR-15 pistol and an AR-15 full-length rifle, you go on to an AR-15 with a 20” OAL, and then one with a 14” barrel length, &c.