The Firing Line Forums - View Single Post - The fine line between AR pistol and SBR. Someone school me please.

marine6680 · April 21, 2018, 08:13 PM

You can not convert an existing AR rifle into a pistol.

You can build a new receiver into a pistol, and then you are fine. The rule of thumb (while not perfect) is... Once a rifle, always a rifle... A pistol can be converted into a rifle, then back into a pistol, so long as you do not make an illegal SBR configuration while doing the conversion... Meaning If you have a pistol, and want to turn it into a rifle, you can not put the stock on first, you must put on the longer barrel first. If you put on a stock first, you have briefly made it an SBR.

Generally, you just have to build the receiver with the brace. Then throw on the upper of your choice.

In 5.56 anything below 10.5in is generally impractical, due to the reduction in velocity and the huge fireball from the muzzle. Good for a range toy, not so good for defense.

A carbine gas system would likely work fine on a 10.5 barrel, but I am no expert in the short barrel configurations, others may disagree.

SB Tactical makes a new brace that has adjustability built in, like a stock. That would be a good brace to go with. Generally, you will have a shorter length of pull than a stock, due to the ATF stating that longer length of pull gets into rifle territory. Think a stock that is fully collapsed or a notch or two out at most.

April 21, 2018, 08:13 PM	#2
marine6680 Senior Member Join Date: July 24, 2012 Location: Parker, CO Posts: 4,594	You can not convert an existing AR rifle into a pistol. You can build a new receiver into a pistol, and then you are fine. The rule of thumb (while not perfect) is... Once a rifle, always a rifle... A pistol can be converted into a rifle, then back into a pistol, so long as you do not make an illegal SBR configuration while doing the conversion... Meaning If you have a pistol, and want to turn it into a rifle, you can not put the stock on first, you must put on the longer barrel first. If you put on a stock first, you have briefly made it an SBR. Generally, you just have to build the receiver with the brace. Then throw on the upper of your choice. In 5.56 anything below 10.5in is generally impractical, due to the reduction in velocity and the huge fireball from the muzzle. Good for a range toy, not so good for defense. A carbine gas system would likely work fine on a 10.5 barrel, but I am no expert in the short barrel configurations, others may disagree. SB Tactical makes a new brace that has adjustability built in, like a stock. That would be a good brace to go with. Generally, you will have a shorter length of pull than a stock, due to the ATF stating that longer length of pull gets into rifle territory. Think a stock that is fully collapsed or a notch or two out at most.