Its not a pistol?

If you registered AW is registered as a rifle then no, you can not convert it to a pistol.

 

Registered Assault Weapons still have to comply with SBR/SBS laws.

Making a firearm, with a less than 16" barrel or less than 26" overall length, from a rifle, would be a SBR under Federal laws [18 USC 921(a)(8)], under CA laws [PC 17170(c)], and under NV laws [NRS 202.275 ~ 2.(a)(2)]

Unless you have BATFE approval, doing this would be a felony (Federal and State).



18 USC 921
(a) As used in this chapter—
(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.

California Penal Code 17170
As used in Sections 16530 and 16640, Sections 17720 to 17730, inclusive, Section 17740, Article 1 (commencing with Section 27500) of Chapter 4 of Division 6 of Title 4, and Article 1 (commencing with Section 33210) of Chapter 8 of Division 10 of Title 4, "short-barreled rifle" means any of the following:
(a) A rifle having a barrel or barrels of less than 16 inches in length.
(b) A rifle with an overall length of less than 26 inches.
(c) Any weapon made from a rifle (whether by alteration, modification, or otherwise) if that weapon, as modified, has an overall length of less than 26 inches or a barrel or barrels of less than 16 inches in length.
(d) Any device that may be readily restored to fire a fixed cartridge which, when so restored, is a device defined in subdivisions (a) to (c), inclusive.
(e) Any part, or combination of parts, designed and intended to convert a device into a device defined in subdivisions (a) to (c), inclusive, or any combination of parts from which a device defined in
subdivisions (a) to (c), inclusive, may be readily assembled if those parts are in the possession or under the control of the same person.

Nevada Revised Statue 202.275
2.  For purposes of this section:
(a) “Short-barreled rifle” means:
(1) A rifle having one or more barrels less than 16 inches in length; or
(2) Any weapon made from a rifle, whether by alteration, modification or other means, with an overall length of less than 26 inches.

 

If you know the SBR laws, then you should know that taking a rifle and reducing the barrel length to less than 16" or reducing the overall length to less than 26", makes it a SBR.
It doesn't matter if it as an arm brace on it or not.

gotcha.   I keep forgetting you can't go rifle to pistol...my bad



 

and you can't build an AR pistol in CA either... you have to buy the AR pistol complete as a pistol using a single shot exemption... and you can't register a stripped lower as a pistol either... pretty shitty

You can make a pistol from an 80% receiver.

This will no longer be possible after the end of the year, right?  The only reason this "works" now is because of the single shot exemption, AFAIK.