Maybe someone here can shed some light on this question...
I have a Group Industries registered lower and a couple of uppers, 10.5" 223 and 22LR and a 20" HB upper.
I also have an old AR15 SP1 I bought new in 1979.  It is in unaltered condition.
Do I have a problem owning both?

I don't think you have a problem so long as the 10.5" upper is never mounted on the SP1 and so long as you continue to own the registered M16.

You do have a problem.  Possession of an SP1 and more than one short upper for your M16 is possessing a short barrelled rifle.  Go look at Bardwell's titleii.com site, there is an atf letter on this exact topic.

Troy, you should reconsider.  This is contrary to ATF's most recent positions.  I would not want to be the test case even if I thought differently.



[url=http://www.titleii.com/Bardwell/atf_letter90.txt]Link to ATF Letter[/url]

Well, if ATF's position is enforced literally as what Mr. Owen says in that letter, then they've got a LOT of doors to kick down. Every single person I know that owns an M16 also owns an AR and several short uppers for the M16.

Pretty much, yes. United States v. Thompson/Center Arms Co., 504 U.S. 505 states in part:

"We also think that a firearm is "made" on facts one step removed from the paradigm of the aggregated parts that can be used for nothing except assembling a firearm. Two courts to our knowledge have dealt in some way with claims that when a gun other than  a firearm was placed together with a further part or parts that would have had no use in association with the gun except to convert it into a firearm, a firearm was produced. See United States v. Kokin, 365 F.2d 595, 596 (CA3) (carbine together with all parts necessary to convert it into a machinegun is a machinegun), cert. denied, 385 U.S. 987, 17 L. Ed. 2d 448, 87 S. Ct. 597 (1966); see also United States v. Zeidman, 444 F.2d 1051, 1053 (CA7 1971) (pistol and attachable shoulder stock found "in different drawers of the same dresser" constitute a short-barreled rifle). Here it is true, of course, that some of the parts could  be used without ever assembling a firearm, but the likelihood of that is belied by the utter uselessness of placing the converting parts with the others except for just such a conversion. Where the evidence in a given case supports a finding of such uselessness, the case falls within the fair intendment of "otherwise producing a firearm." See 26 U. S. C. § 5845(i)."

Of course, if the extra parts are NOT utterly useless except to make an illegal SBR (because you have a registered SBR or MG) then possession of additional <16" uppers should be fine.

It seems, therefore, that ATF's "constructive possession" theory fails if the unassembled part has a legal use by the owner, even if it also has an illegal use.

If you register the SP-1 as an SBR, you would be in the clear with no worries.  Just don't maintain any spare M16 fire control parts.

{edited because I couldn't spell "SBR"}

I think ATF disagrees with that view, whether or not it's correct.  The ATF letter dates back two years, Thompson is a 92 decision.

I think they distinguish Thompson on the grounds that it provided a legal configuration, the pistol barrel, and another legal configuration, the stock and rifle barrel.  

In the question raised, if one of the two short uppers is put on the M16, the only legal configuration that remains with the AR-15 and the other short upper is illegal short barrel rifle.

Look, I'm not necessarily saying ATF's worldview is correct; however, their position in the letter is crystal clear that they view this as illegal.  So proceed at your own risk.  I have moved my two Bushmaster AR-15's out of my house since I got an M16 to avoid this exact problem.  Besides, when you have an M16, an AR-15 feels kind of passe anyway.