So I have what may be a tough question for you all.  I'm looking at building a pistol with the ARAK 21 upper.  I'm going to SBR it eventually, but I'm moving soon and don't want the hassle right now.  I'm planning on buying the 12.5 inch barrel (and cutting it to 11-11.5) as well as the 20 inch barrel.  They swap out in only a few minutes.  From what I've read, once you build a lower as a pistol, you can freely change it to a rifle and back to a pistol at any time.  I've also read that using the UBR buffer tube is completely acceptable.  So here is my question:

If I build my lower as a pistol with the UBR buffer tube, can I have the UBR butt stock in my possession, provided that I only install it after I've changed my barrel from the 11" to the 20" (and of course remove it first before reinstalling the 11" barrel)?

Also, can someone please explain the 26" rule to me?  The ARAK upper does not require a buffer spring/buffer/tube, so if I don't need it, I may not install it at all.  Thank you!

- Stock: as long as you have a legal "useful purpose" for the stock other than making an NFA firearm, you're okay. Meaning, you could have the tube for it on the pistol, and the stock would have a legal purpose if you also possess an installable long barrel, or if you have another rifle with the UBR setup, as an extra stock would just be a legal spare part.

However, if all you owned was an AR pistol, possessing any stock would be unwise, and one made to attach to the type buffer tube you have would certainly be making an NFA firearm under the ruling (parts do not have to actually be assembled to have "made" one).

Anyway, the test is not whether you can make something illegal with anything you have, but rather whether you can also make something legal with it.

- 26": This is only relative to an AR pistol in that if indeed it is 26" or more in legal overall length, you may use a vertical forward grip, at which point it becomes a legal "firearm", and magically reverts to a "handgun" when removed. Note that muzzle device only counts toward OAL if permanently affixed.

- OS

Thank you, this definitely clears things up for me!  I'm planning to use just a hand stop, if anything, on the pistol, so I wouldn't even need the buffer tube at all in that case.  Good to know.  Thanks again!

As a ARAK owner I'll give you my 2 cents. For one I don't think you'll be shortening the barrel from the 12.5" length. The reasons:  #1 the barrel assembly cannot be "chucked up" like a traditional AR barrel to be cut and threaded. #2 the profile in which Faxon builds their barrels at does not provide enough "meat" to cut and re-thread. #3 and most importantly Bill Faxon and crew have already done the R&D on barrel length and determined that 12.5 is the shortest length the ARAK long stroke piston system will reliably function at.

This is excellent information, thank you very much! How do you like your upper? Ever had any issues?

I have the 16 inch 5.56/300blk combo. Works great, ultra reliable. Weight is center forward so you would want tho still use a buffer tube and probably a SB15 arm brace to balance it out.

Ultra reliable is what I'm looking for. Thank you for the advice!

hi Folks, I am new to AR15 Forums and not very familiar with lawful AR pistol posession. I just want to know if I understand properly what OS said.
In my case, I can own an AR Pistol and at the same time own a regular 16" AR (with 6-position CAR stock) without violating NFA laws?
Sorry for this question, as I am not well informed on this but I intend to. Thanks.

Yes!  Jun take the time to read through the stickied posts at the top of the AR Pistol section...so good info and reading.

Yep. In that case, you may have as many stocks as you like, actually, also vertical forward grips, the only other possible bugaboo for AR pistols under 26". Multiples of parts are fine, if one can be used in a legal useful purpose, so can any of the others.

Although if out and about with the pistol, even though it would technically be legal as long as you have the rifle with you, probably not wise to also have an extra stock or vertical forward grip with ya, no sense trolling. :)

- OS

I got it now. Thank you LR and OS for your input.