I built a .300 Blackout pistol legally using the Sig brace like the rest of North America and would like to get a .223 pistol upper for it as well.
I also have 2 complete AR carbines, one .223" and the other .300 Blackout.
Would having the extra .223" pistol upper in my possession be considered a potential SBR possession?
I believe it would, something that simple suddenly gets complicated.
All I want to do is shoot some .223 and even .22 LR out of my pistol build by swapping out another upper, I have swapped carbine uppers many times since both are carbine length.
I guess I just cannot have that much fun.

I think it has been well discussed that having extra uppers for your pistol/sbr is fine, I think where it gets complicated is if you have two spare pistol uppers lets say...and so happen to have a few rifle lowers sitting around...at least thats how I take it. I am by no means giving legal advise....please be aware I am a redneck.

There is no such thing as a pistol upper only a barrel less than 16" or greater than 16". Having other short barrels for a pistol lower shows that the short barrels could be used for lawful purposes. My opinion is that if you have a pistol lower and a rifle lower based on registration you are covered from intent of having an SBR. Not sure how others will rule on this.

The short barrel uppers are only intended to be used on my pistol lower.
If I wanted an SBR, I could have gone that route.
Just asking for advice and opinions, not legal advice.

What type of advice are you asking for if not the legality of owing more short barreled uppers than pistol lowers?

I have never seen a case with this exact scenario.  But, I always operated on the assumption that if the feds or the state want to charge you with something, they will, regardless of how many lowers or upper you own and just getting the bogus charges dropped could easily cost $10k or much much more.

If you want to be more safe, just buy another pistol lower.  I always had a pistol lower for every upper with a barrel less than 16 inches.  They cost less than $200 to build up and I felt better that way.

Now, from a pure utility standpoint, why in the world would you actually WANT a sig brace over an SBR?

Easy solution, I will simply build a 5.56" AR pistol. Done deal.
Yes, I am looking at polymer as well.
The cover of Shotgun News, I'd say it here for real.