AR Pistol-Barrel Length

**SteveO666** · March 28th, 2016, 08:55 PM

I am looking at possibly adding to my collection and thinking of a 9mm AR, either rifle or pistol. If the lower is a dedicated pistol lower is there a Maximum Barrel length? While it may not make sense to put a 16"barrel on a pistol is it illegal?
Also if I have a 16" upper can I legally swap it between 2 lowers(1 dedicated Pistol and 1 Rifle)?

The reason I am asking is in my online shopping I am seeing complete uppers listed has either carbine or pistol length(usually<11") and not sure if that is just for marketing or legal reasons.

Thanks in advance,
Steve

**awfroadan** · March 29th, 2016, 10:28 AM

If you have a pistol lower you can put any length barrel on it you want as far as I know. 9mm will not have a gas tube. I have a 5" 9mm AR SBR that I built from scratch and it is a great accurate rifle. I wouldn't go any longer than that personally if you're doing a pistol. You don't gain much after 5 inches and that length helps you keep most ammo subsonic if you plan on suppressing it in the future. You're pretty close so let me know if you have questions or could use a hand.

**danhr** · March 29th, 2016, 11:41 AM

You are good to go! You can throw a 16"+ upper on a pistol legally, as long as you don't have a stock on it or don't shoulder a sig brace.

A 16" upper will more than likely get you a 26"+ over all length.... which means you can use a vertical grip on your 16" upper, on a pistol registered lower.

**knight0334** · March 29th, 2016, 11:49 AM

There is no maximum allowed barrel length set in PA or Federal law for a handgun.

PA law does limit what is considered a "firearm" to a barrel length of 15" OR a overall of 26" - whichever is longer. (a 15.00001" barreled handgun, under 26" OAL is still a "firearm")

A handgun with a barrel 6 miles long is still a handgun to federal law.

**GunLawyer001** · March 29th, 2016, 12:20 PM

“Firearm.” Any pistol or revolver with a barrel length less than 15 inches, any shotgun with a barrel length less than 18 inches or any rifle with a barrel length less than 16 inches, or any pistol, revolver, rifle or shotgun with an overall length of less than 26 inches. The barrel length of a firearm shall be determined by measuring from the muzzle of the barrel to the face of the closed action, bolt or cylinder, whichever is applicable.

§ 6106.1. Carrying loaded weapons other than firearms

(a) General rule.-- Except as provided in Title 34 (relating to game), no person shall carry a loaded pistol, revolver, shotgun or rifle, other than a firearm as defined in section 6102 (relating to definitions), in any vehicle. The provisions of this section shall not apply to persons excepted from the requirement of a license to carry firearms under section 6106(b)(1), (2), (5) or (6) (relating to firearms not to be carried without a license) nor shall the provisions of this section be construed to permit persons to carry firearms in a vehicle where such conduct is prohibited by section 6106.
(b) Penalty.--A person who violates the provisions of this section commits a summary offense.

**Fortytwo** · March 29th, 2016, 03:00 PM

Originally Posted by SteveO666

The reason I am asking is in my online shopping I am seeing complete uppers listed has either carbine or pistol length(usually<11") and not sure if that is just for marketing or legal reasons.

I think usually the carbine / pistol length entry in the upper's description tells the type of gas system that the upper has.