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SIG SAUER are the guys who make the now infamous pistol arm brace for AR-15 pistols that looks remarkably like a stock. And works kinda like a stock. A really, really crappy stock. Anyway, there has been much chatter on the internet about whether the ATF will get their knickers in a twist about people misusing the arm brace and subsequently change their minds on the legality of the whole thing. Thankfully, the ATF has just released a letter clarifying their position and confirming what we’ve been saying this whole time: the arm brace is here to stay. Thanks to SIG SAUER for sending it along, read it after the break . . .

Dear Sgt. Bradley:

This is in response to your communication dated January 24, 2014, to the Bureau of Alcohol, tobacco, Firearms and Explosives (ATF). Your e-mail was forwarded to the ATF Firearms technology Branch (FTB), Martinsburg, West Virginia, for reply. In your note, you ask about firing an AR-15 type pistol from the shoulder; specifically, if doing so would cause the pistol to be reclassified as a Short Barreled Rifle (SBR).

For the following reasons, we have determined that firing a pistol from the shoulder would not cause the pistol to be reclassified as an SBR:

FTB classifies weapons based on their physical design characteristics. While the usage/functionality of the weapon does influence the intended design, it is not the sole criteria for determining the classification of a weapon. Generally speaking, we do not classify weapons based on how an individual uses a weapon.

FTB has previously determined (see FTB #99146) that the firing of a weapon from a particular position, such as placing the receiver extention of an AR-15 type pistol on the user’s shoulder, does not change the classification of a weapon. Further, certain firearm accessories such as the SIG stability brace have not been classified by the FTB as shoulder stocks and, therefore, using the brace improperly does not constitute a design change. Using an accessory improperly would not change the classification of a weapon under Federal law. However, the FTB cannot recommend using a weapon (or weapon accessory) in a manner not intended by the manufacturer.

We thank you for your inquiry and trust the foregoing has been responsive.

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    • If you were to look in the ATF’s basement, you’d surely find some large, dried pods….

      • DO note that the ATF office in question is located in what most of the politico end of the ATF would have to consider a backwater hell. The kind of people who get their knickers in a wad about these things are the kind who don’t really like the concept of going to one of those horrible nasty disgusting hick Flyover States…. The kind of people who get assigned there are likely the kind of people that the political officers don’t like.

        Kinda like throwing Brer Rabbit in to the briar patch.

    • I find it illogical. It basically is a stock. It looks like a stock, it works like a stock. I’d suspect Sig even designed it with this “improper” use in mind, because I doubt many people buy these things and strap them to their forearms.

      Of course I find the legal restrictions on firearms due to a barrel being 15.9″ versus 16.0″ even more illogical than the remainder of the gun laws, which are pretty damn stupid.

      That being said, I just ordered my sig brace, and might not bother to start a form 1 if/when the WA SBR bill passes. And yes, I will be using mine “improperly”.

      • Sig didn’t design it, they just bought the rights to it. It was designed by a man who made it for a war vet who lost an arm so needed it to help him shoot with his remaining one. It was very much designed for that reason, but I bet that is not the the intent Sig had in mind when they bought it.

      • Good news! The Governor signed the SBR bill, SB 5956, in a signing ceremony on April 2nd. The law should go into effect around June 12th (90 days after the end of the session).

      • Why would you even comment, you said nothing. What you just said was about as uninteresting as reading BATF rules and regs. Why come on here and comment about something you dont really agree with, just to say your going to buy one and use it improperly. What a waste of time.

  1. IMHO it isn’t even a crappy stock. With the exception of the difficulty in moving it forwards and back — although you CAN adjust it like 3″ in and out from center — it feels just like a normal M4 stock. It’s a perfectly good stock. As in this review:

    I’m glad to see this, because it sure sounds a whole heck of a lot like what I wrote in that review:

    “The BATFE has stated that the SB15 brace was not designed or intended to be a shoulder stock when attached to a pistol. Therefore, a pistol remains a pistol with this unit attached. The law applies to the design intention, not the actual usage. Note that it doesn’t say “when attached to your arm.” By way of example, a crowbar might work great as a hammer, but it will always remain a crowbar. It just so happens that this brace also works great as a shoulder stock.”

    • It works fine as a stock. It actually makes me regret registering the lower as an SBR, there’s no point now. I guess I can use a real one, but in the pistol config I don’t have to bother with the stupid state to state transport laws. Going to try it with a 450 Bushmaster 11.5″ upper, see if its sat with that too.

      • In addition to paying 200$ for the tax stamp, SBRs cannot be carried concealed. So a pistol is a better option.

        • Not true at the federal level. The NFA-34 and other federal laws are completely silent on the issue of concealed carry of SBRs.

          And not true at the state level, either, in most states. Some states have a concealed HANDGUN law. Many others have a concealed WEAPON law that does not differentiate between handguns and other firearms, Title I or Title II.

      • You should pay your $200 transfer tax and properly register your short barrel (sawn off!) rifle. We don’t need the ATF declaring a ‘new’ pistol round.

        • Well, for .223 and 7.62×39, you’d be too late, they already have. For the other common AR calibers, there’s no AP ammo, anyway, as far as I know.

    • I have a Mech Tech .45ACP “pistol accessory” with a Glock G21SF lower that is crying out from the safe, “Sig me!” Why not? I like EO’s on my pistols. Sometimes.

  2. Ain’t this an April fools joke?…………..Oh, OK it’s the 3rd already…..woo hoo…..

  3. That’s awesome…SBR like performance from AR pistols now. I wonder if the ruling would be the same, shoulder firing an AR pistol with a CAA side saddle added to the buffer tube? I’m assuming so, as it’s even less of a “stock-like” apparatus than the Sig brace is.

  4. I used to wonder, but now I KNOW… The ATF is messing with our heads. I bet they laughed their asses off after they sent this letter.

  5. The ATF really had no choice in the matter. Either they stick with designed intent or they risk the whole structure coming crashing down. The ATF lost vs Thompson with the contender pistol/rifle combo, changing now on this would very likely lead to another very public “Loss” for them.

      • What difference would it make?

        There’s no cheap steel-core .300 BO being imported, so being classified as a pistol cartridge would have absolutely no effect on the price or availability of .300 BO ammunition.

    • The ATF doesn’t really care how much money the generate through the NFA as they don’t get to keep much of it. That’s why we have so few examiners. If they wanted our money, they would streamline the registration process to kick them out quickly. As it stands right now they fall further and further behind every month to the point where it’s almost a year to get a Form 1 or 4 approved. That’s killing the interest in all things NFA for many people.

    • Yeah, check out the pics and such in the review that I linked higher up in the comments. You don’t have to push the SB15 all the way to the receiver end plate. It’s solid out to quite a few inches back from that. You can’t get it to feel like an M4 stock at the longest settings, but you can definitely get it to feel as good as an M4 stock on the shorter settings.

  6. So manufacture a real stock that isnt intended to be used as a stock so we can all use it not as intended.

    Seems like this whole “intent” thing is an admission the whole system is based on bullshit but theyre all still too happy to lock you away for violating bullshit.

    The ATF would make Kafkas head explode.

    • Actually I’m glad the ATF made this illogical ruling. It opens the door for the potential of SBR/SBS being removed from the NFA.

      We’re within inches of legally challenging the NFA, folks. No joke. I would bet within a decade it could happen – maybe not for MGs, but at least SBR/SBS and suppressors.

      • I would rather have all of the AK and AR ‘pistol’ sawn off rifles be put under the NFA and have the ‘pistol’ ammunition ban lifted.

        I guess I’m an old man because I’m still sore about 7.62×39 being declared pistol ammo because Olympic Arms built a prototype cop killer gun. The inexpensive surplus ammo went away quicker than overnight.

        Unless robbing a liquor store is a legitimate use there are no legitimate uses for these stupid toys.

        • You are simply a fool.

          The “pistol” ammo rulings mean nothing now. There isn’t a huge supply of cheap steel-core 7.62×39 ball out there waiting to be imported. The Russian ammo has been cut-off just as the Chinese was, irregardless of it being lead-core or steel-core.

          You would throw everyone under the bus for your fantasies about the “good old days” when you could stagger out of your trailer to bump-fire 7-cent ammo out of your Tapco-fucked AK. Those days are not coming back.

  7. The atf has IMO now confirmed that even they don’t feel sbrs are any more dangerous than a ‘normal’ gun.

    • I really think bull-pup designs have fairly mauled the meaning of SBR’s. Who can’t manage to hide a carbine under his raincoat today? And who would bother? The SBR rule isn’t needed, now more than ever.

  8. I had one of these on my pistol until the paperwork came back for the SBR. This gadget is fine as far as it goes, but a proper, fully adjustable stock is worlds better. The tax stamp and wait sucks, but in the end, you get a better gun.

    This thing works fine in a pinch, but it’s a bit too short to be really effective and comfortable for a long range session or class.

    • I recently got a letter from the ATF that said it was fine for me to convert my SBR back to its original pistol format and move it across state lines as long as its not in an SBR configuration. Does that read right? The letters are binding for the person who gets it, right?

      • No…the letters are not binding. I have spoken and gotten letters from ATF/FTB and they have told me that letters are done for everyone. That’s why the letter for the Slide fire is for everyone and the Taccon and all the other products that FTB has written a ruling on. Can you imagine if FTB had to write a letter that gave permission to each person allowing them to use said product in said manner???? There are only 15 or so agents in that section…nothing would ever get done.

      • ATF’s position on SBRs has always been that an SBR only exists when it is assembled as an SBR, or when the parts to assemble the SBR are “under the control” of the same person as the receiver.

        It has always been legal to remove the SBR-specific parts — the short barrel and/or the shoulder stock — and then treat the resulting non-SBR-configured firearm as an ordinary rifle or pistol. Check the ATF’s FAQ on their website, it is covered there.

  9. So is a used oil filter legal just because you happen to put it on a gun after taking it off the car…?

        • Its the adapter AND the oil filter, both need to be serial numbered, and you can’t replace the filter since its considered a component. Basically renders the legal idea pointless once the filter fills up with lead and everything gets blown out.

    • Why not? What crook is going to carry a Fram around? But without the specifically-designed mounting attachment for “turning your oil filter into a suppressor” the used oil filter will require massive duct taping, no?

  10. I think the underfolder stock on my AK looks more like an arm stabilizer.

    I’ve got a golden tickeeeeet….

  11. I wonder if building a “plug” for the back to remove the air gaps would still constitute “using the accessory improperly”? It would be easy to 3D print such a piece, even have mounts for pads.

    • Don’t change the design. If you start to change the design then you start to change the design intent and none of these rulings will necessarily apply. Modify it at all and it isn’t what it was when the ATF determined it to be a brace and NOT a butt stock. My $0.02 is leave it exactly as-is.

  12. Something tells me they’ll still arrest you for doing it, drag you through years of expensive trials, and then lose leaving you penniless…. just cause they can.

  13. I have one on my pap M92. Its actually a pretty good stock… especially when you attach a 2 inch wide sling mount to the brace tube, effectively lengthening the pull by 2 inches.

  14. The brace is a little short to use a a stock. Pull it back a bit works, but after extended firing is tends to slide forward. Solution: Wrap any exposed portion of the buffer tube in paracord, and stuff the buffer opening of the brace with a PVC pipe cap.

    • Nose to charging handle, square up, and shoot that way instead of blading. It shortens the length of pull you need.

    • I would be very wary of modifying the brace in any way. The ATF ruling will only cover 100% factory condition. Paracord/texture tape may be an arguable superficial thing, but stuffing a cap in there gives me major pause.

    • You could also use some Rave hairspray on the buffer tube. Basically the cheaper the hair spray the better. I use the same trick on motorcycle grips. Spray it on, slide on the Sig brace, then let it dry.

  15. I’ll just keep my mouth shut on this one.. and maybe pick up a new accessory. Or three.

  16. Just the goofiest thing…

    I was in a training class last Saturday with a guy using his Sig “pistol” with this stock. He ran the whole class with it functioning as a SBR.

    He keeps the ATF letter in the storage compartment in the pistol grip.

  17. Keep in mind, these ATF determination letters are barely worth the paper they are written on. Ask EP Armory and Ares Armor.

    • Yeah I file this stock contraption under the category of people who pin a Noveske KX3 on a 13.7″ barrel or those idiotic Spikes Tactical fake suppressors. Like some kid who goes out and gets an M Sport body kit and badges for his 318i. Just functionless crap that makes something look cool (although thats up for debate).

      Save the money from buying this gimmick stock and pay the $200 and register it as an SBR. If SBR’s are illegal where you live then just build a 16 inch carbine with a real collapsible stock so you arent married to a pin welded muzzle device and dont have to register your lower. One of the huge points of an SBR is that it can have a suppressor mounted and still be as short as a normal carbine. If you live where SBR’s are illegal supressors are probably niet too so you are just losing performance in order to try and look cool.

      If you have enough money to be playing with AR-15’s then you have 200 to spare for a tax stamp. If you think having a lower registered with the ATF is somehow worse than one you bought by giving your SSN, and the serials of the lower to the NICS background check system you are woefully naive, just our brethren in CT.

      Call me old fashioned, I just dont get it.

      • This gets rid of alot of the problems of the NFA with regards to moving across state lines. Its not a problem with silencers, but SBR’s you have to get written months in advance ATF permission to cross state lines while in the SBR configuration. You could pop on a 16″ upper, but why when you can just throw that on a regular non-SBR lower? The brace works fine as a stock. Not great but much better than a padded buffer tube. Some states also have stupid hunting laws where an AR pistol is legal while a rifle in the same caliber would be illegal. There’s also the whole not having to wait 14 months for permission to build the dang thing.

      • Said it before. Concealed carry in most states will disallow SBRs. Why carry an SBR? Any situation that would require more accuracy.

        • You were wrong the first time you said it.

          Repeating your misinformation doesn’t make it any less incorrect.

      • > Save the money from buying this gimmick stock…I just don’t get it.

        Where this is advantageous is in states that do not allow rifle carry in a vehicle, like Michigan. This gives you a rifle-like legal pistol.

    • It doesn’t work, I tried it. The A2 buffer tube is too thin, the Sig brace slides right over all wobbly.

  18. What kind of idiot raises his head from anonymity and asks for permission from mommy-government when SIG clearly provides paperwork for it’s legality and there are numerous sites that further explain that the it’s the intent of the item and not how you personally use it.

    Some people are just naturally sheep….even if they are well armed sheep.

  19. Just ordered my Sig brace online today with free shipping. Never really wanted a AR15 pistol… NOW I HAVE TO HAVE ONE!

  20. It’s an entirely logical interpretation and the only possible one – or else bump-firing a rifle would make it full auto, firing a handgun with two hands would make it an sbr, etc, etc. Has to be design intent. Can see irritation by some and elation by others, perhaps understandably so. it doesnt change world however. It’s not a stock and doesnt make it an sbr. Close, but no cigar. Not adjustable/collapsible, has an ‘open back’ and straps on it (that you cant take off or modify!), still can’t run a VFG, etc. Wonder what folks who get all in a stitch about it being illogical think about bullpups. As someone said above, they had no choice but to stay with design intent, not one different possible usage, or else the whole muddled thing falls apart. So just roll with it.

  21. …for those who went SBR, it’s still worth the $200. Trust me. For those who can’t in their State, it’s pretty cool.

  22. Not trying to poo poo this but it looks like another gadget that will wind up in that junk box after the coolness wears off. That’s why the ATF approved it. But as long as some people are happy with it is all that matters.

    I have a long list of new fangled gadgets in boxes in the garage. I’m not adding anymore. I’ll pass on this.

  23. I’m with you fred just like the slide fire stock and trigger attachments it’ll wind up with the rest of the new legal way to get around laws stuff that nobody plays with anymore

  24. No offense – can we get this in writing. Like a copy of the original ATF letter so I can print it off and insert it in the gun case with the gun??

  25. By this logic, the ol’ shoestring machine gun cannot be illegal, because it’s just a misuse of a semi auto rifle and a shoe string. My understanding is that while string was once banned by the ATF, they reversed that decision before confiscation began, but the USE of string as a machine gun is still illegal.

    • I don’t think it’s safe to apply this ‘logic’ to other applications, as everyone seems to want to extrapolate on this. ATF’s ‘interpretations’ on this are specific to the SIG braces. It’s a muddled mess of course, but it is what it is. It’s not supposed to ‘make sense’. It’s the ATF after all. It would work the other way around too… Should a bullpup under 26″ require a tax stamp? Didn’t think so. Don’t think of this as logic, but specific interpretations to an already muddled and completely unnecessary NFA law. The SB-15 does not make a pistol into an SBR. It’s works quite crappily shouldered. It’s not collapsible/adjustable, has straps on it (that you cannot remove or modify!), you still can’t run a VFG. Like I said above, it’s still worth the $200 to SBR, but for those who can’t in their area, it’s a pretty cool alternative. There are of course other advantages to it still remaining a pistol as well (in regards to transporting, etc), but it is still not an SBR. So just accept it for what it is and move on. If you think about it, any ‘interpretation’ the other way would have turned everything on it’s head. Would bump-firing a rifle then make it full-auto? They have to stick with design intent. It’s what the whole system is based on. Try to avoid extrapolating and applying to other scenarios. Thank you and have a nice day.

  26. One a side note, I have never seen so many people get their panties in a bunch over a good bit of news.

    Either they are upset because they spent $200 to SBR (and should not be, because it’s still worth it, as I tried to outline above). So they lash out with all kinds of grumpy comments.

    Or they think that the existing NFA laws on SBR all made sense and this doesn’t somehow and think NOW that the whole thing should just be thrown out (as if it didn’t, and shouldn’t have been before)

    Or they then try to extrapolate this ‘interpretation’ and apply it to every other thing that they want, but can’t get right now. Or every other thing that doesn’t make sense (when none of it really does. ie – think bullpups).

    Not sure… Just a little telling to see some people’s responses. Hearing a lot of whining.

    Then you have people that all of a sudden want to get an AR pistol just because of this. As I think Nick stated in his first review, which I agree with, SB-15 isn’t a reason to get an AR pistol, but it does make them suck a little less (compared to shouldering a buffer tube). There are still many other laws you have to be aware of regarding AR pistols, and personally, in 5.56, I think they do still kinda suck. Now 300BLK is a different story…. (But you better have a stack of cash for ammo or be able to reload)

    • I don’t own any ARs, so it doesn’t matter to me either way. I’m just amused more than anything that there’s still no logic applied. Come on, it’s obviously a shoulder stock. Of course if the ATF could apply logic, there would be no such thing as an SBR anyway and it wouldn’t matter. I don’t necessarily want them to rule in our favor all the time, I just want them to rule with logic and consistency. Might as well be wishing for a purple unicorn though.

      • exactly. and ATF doesn’t do purple unicorns.

        It’s really not a stock though. Own one, then tell me. It’s works quite crappily as a ‘stock’. It may look like a stock, and it’s definitely better than shouldering a buffer tube, but it’s really not a stock. Tried to outline why I think that above.

  27. I’ve seen this supposed ‘official’ letter a few other places, but none of the people/sites posting it show who signed this letter. That’s pretty important don’t you think? I can find no reference to this letter, the FTB # specified or several key phrases mentioned in it on the ATF web site.

    This would be great if true, but I cannot find enough evidence to suggest it is. Not that the ATF has any business telling us what kind of firearm we’re ‘allowed’ to use anyway. The entire Gun Control Act of 1968 is unConstitutional. Let’s go back and ask George Washington and the gang if the Brits should be allowed to tell them what arms they’re allowed to have. Give the very people they wrote the 2nd Amendment to protect us against the power to tell us what arms we’re allowed to use? I think any objective person can imagine the fiery “HELL NO!!” to that question.

  28. This is a boon for a variety of reasons.

    FYI, take the ends of the brace, fold them inward and tighten the strap, you now have a very solid brace with the same footprint as a standard m4 stock

    Establish length of pull, then pull the brace back another two inches and spray tube with either cheap hairspray or thin bead of gorilla glue push forward and rotate 360 degrees, now you have what is essence a “sully” stock.

    Option 2, take an ak/556 variant , add buffer tube, brace and ace hinge. Now you have a very compact pistol in a rifle caliber.

    Now as to why. A pistol falls under your CCH or CHL and DOES NOT fall under most wildlife codes concerning loaded rifles in vehicles.

    The brace when folded as described allows for much easier cheek weld than a buffer tube alone

    You can cross state lines without notifying ATF as you would with an SBR.

    Its more than just the $200 and the year wait, though having one in you stable while waiting on the form1 is a bonus.

    I have a couple of SBRs and I still have a SIG Piston pistol for the ease of use.

  29. I don’t know guys, I read all the postings above and every one has a good idea about the Sig Brace. But at my advanced ( LOL ) age, I think what I might do is ” just for poop and giggles ” is get a Mini – 14 tactical with a flash suppressor and protected front sight and then go with a folding stock for starters. that would be my base weapon, the bad part is that I don’t know if I can or could get a .22 adapter for it. I looked at the Sig Brace yesterday at the local gun shop ( $12 to $1300 price range ) and yes it looks nice and no I’m not crazy about going SBR for obvious reasons. But then again I probably don’t know what I’m talking about anyway.

  30. Well, so much for their official approval just rescinded. This is the perfect time for Congress to use this confusion to remove the inept ATF from the burden of these interpretations by eliminating the NFA registry. They will squander this opportunity, of course.

    • This is true, if the above letter is true, there is ALOT of people who have never seen It

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