In this ATF letter, the author asked the ATF’s opinion on a number of great AR pistol related questions.  I am paraphrasing a few points I found important to help folks doing full text searches for opinions:

1) An AR lower receiver is neither pistol nor rifle until it is built the first time.  If you want to make a pistol, a lower receiver must *never* have been built in a rifle configuration.

2) AR pistols do not have a barrel length restriction.

3) AR handguards can be used on an AR pistol

4) An AR rifle and pistol can be in the same household — note, and this is a personal comment, what got a guy in trouble years ago was that he had only an AR rifle and a pistol upper with no lower to mount it on.  I don’t remember all of the details but the main thing here is that you never want it to look like the only reason you have a pistol/SBR upper is to put in on your AR that is legally classified as a rifle.

5)  Magpul angled fore grips (AFGs) are permissible on the bottom accessory/picatinny rail.

I recommend people print and keep copies of letters just in case they need to show someone that some aspect of a weapon was “approved” by the ATF at some point.  Just bear in mind that ATF letters are not absolutes but it helps to have them handy if asked.  A state or local government may have their own more restrictive regulations as well so this may not mean AFGs are legal for everyone everywhere.

Legal Disclaimer:  I am not an attorney and am not giving legal advice.  I am just passing this information along and it is up to you to determine what you can/can’t do.