If I own a legal pistol lower with a 7" barrel can I legally put a car stock on it or does that make it a sbr?

Thanks.

to legaly put a stock on a pistol the barrel lenght must be 16 inches or longer. Also by doing this at least on a AR you can never Irepeat NEVER make it back into a pistol
unless its registred as a SBR

One other thing to put a Car stock on a SBR the lower has to be pre ban/CB

Actually, as long as the lower started out as a pistol, you can put a 16" or greater barrel on it, and then put a stock on it, legally.  Having done so, you can remove the stock, and again put a short barrel on it, as a pistol.

Pistol can go to rifle configuration and back without a tax stamp.  Rifle can't go to pistol.

The collapsible stock on an SBR info is correct - but would only apply to a pistol with a long barrel and shoulder stock if collapsible stock is on the banned features list for a post-ban PISTOL.

Call the ATF, NFA branch at 202-927-8330.
Ask them the same question.
The TRUTH will suprise you.

I would suggest writing them.  Why, documentation.  That way if the ATF agent who said "bla, bla" is wrong, it's not his/their word against yours.  It takes some time.  My little bit.

But to my understanding, a pistol can be changed into a rifle and back again (like making a 1911 rifle...16" barrel and then a stock...attatched in that order).  But, the AR might be different....assuming could be a bad move.

On going from pistol to stocked rifle and back without being subject to the NFA:
[url]http://www.cs.cmu.edu/afs/cs.cmu.edu/user/wbardwel/public/nfalist/rr_61203.txt[/url]

And in particular, the relevant section: