I always wanted to try out one of the Sig folding arm braces on a pistol, but didn’t really want to spend the money if it ended up being garbage. Fortunately I came by one super cheap, and after some research found that you can in fact use them with a folding stock adapter and be legal. Above is the final product next to my 8″ AR SBR.
I started with one of the $400 Yugo PAP pistols that were floating around a year or so ago. By itself it was very well fitted (by AK standards) rifle, but obviously it was trash to shoot. I’m not (usually) a drunk redneck, so firing wildly into the side of a hill or car isn’t something that I really care to do.
After some research, I ordered an ACE folding stock with pignose adapter to accept an AR gas tube. My folding brace was the SB15, and I also got the Ultimate Arms Extended Brace Tube Stop (gen 2). I had to drill/tap the rear of the receiver to accept the folding stock adapter, which is no biggie if you have the tools (a drill and a set of taps).
At this point I was expecting some rattly piece of trash, but everything fit together very snugly. The arm brace stays on very well and doesn’t slide all over the place, thanks to the brace tube stop. It is also very difficult to slide off, even if it’s swinging wildly up against your body. My only real complaint is that the QD adapter is on the wrong side as you can see in the pictures below. I guess that goes with the territory, since everything is backwards on an AK pattern rifle.
In the bottom picture, the arm brace is not at an angle, it’s just the angle I took the photo with. There is actually a fair amount of adjustment as far as y-height with the arm brace.
Total weight (with loaded mag) is about 8.7 pounds. Heavy! I’m a tall guy (6’4″) and it actually fits me pretty well as far as how long the arm brace is. I’m not sure on the current legality of the arm braces (they seem to still be legal, a ton of people make them now besides SIG), but at the time, they were illegal to actually shoulder and fire. So I obviously never did that.