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Only a few years ago the SB Tactical arm brace elevated the obscure AR-15 pistol from the level of occasional range toy and oddity to functional and desirable firearm. Thanks to our mercurial friends at the ATF, there was once a question about the legality of these devices, but that has now been satisfactorily resolved.

SB Tactical introduced a new extension to their line last year that not only extended their product line but actually expands the way their braces could be used: the extendable adjustable PSB.

While the original stabilizing brace was a great product, there were some downsides. For one, it was a bit bulky with flared flaps designed to wrap around your arm. It was also fixed in place and couldn’t be adjusted to make the gun more compact if needed. There was definitely room for improvement, and the PSB looks to hit all those marks.

With the PSB, SB Tactical has chosen a design that more closely resembles the original stabilizing brace that they submitted to the ATF for approval many moons ago. This slimmer configuration was replaced by the more flared version we’re familiar with because SB was afraid that the ATF might pull the plug if they made it too easy to shoulder.

It seems like their fears were well-founded — the ATF did exactly that as soon as competitors like Shockwave got into the game with their significantly slimmer single blade designs. But now that they have the all clear, SBT is playing catch-up.

As you’d expect, the slim Heidi Klum edition PSB doesn’t work nearly as well as the bulkier Kim Kardashian model at performing its original job – clamping onto your arm. The PSB’s straight flaps do in fact function and will grip your arm sufficiently to fire the pistol as intended, but it not quite as well as the original.

Then again, firing the handgun in a manner the manufacturer doesn’t intend is much more comfortable. As with the original, the short length of pull on the PSB when shouldered makes it a little awkward at first, but with a little practice even larger shooters should be just fine.

You may have noticed that the arm brace was specifically marketed for the SIG MPX, but I have it mounted here on my MCX handgun (specifically the .300 AAC Blackout version). While the PSB may not have the manufacturer’s blessing for this application it nevertheless fits without complaint.

The real party trick here is the ability for the arm brace to retract and make the firearm even more compact. As I said, the original brace was good, but bulky. With the new PSB on board the gun can be compressed  for storage and carted around much more easily and stealthily while still giving the shooter the option to extend it for more stability.

The collapsibility is great, but is it $100 great? With the original SB15 still having an MSRP of $149.99 you’ll pay an added Benjamin for the ability to extend and retract your arm brace. There’s little doubt that it’s still much cheaper and quicker than a tax stamp, but I feel like we may be inching closer to the edge of that price versus utility debate.

For those who own an MPX or MCX this makes tons of sense. But if you raise the price another $50 and ask me again I’m not sure I’d have the same reaction.

Specifications: SB Tactical PSB
MSRP: $249.99 ($199.99 on Optics Planet)

Ratings (out of of five stars):

Functionality * * * *
It works beautifully for the unintended purpose of shouldering, less so when strapping one onto your arm. And I’m okay with that.

Quality * * * *
Extends and retracts without an issue and feels comfortable against my cheek. The mounting bracket isn’t perfectly mated to the receiver, but then again it was designed for an MPX and I slapped mine on an MCX.

Overall Ratings * * * *
It may not be perfect, but it’s the best tool for the job right now.

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  1. I have the original brace on my AAC 9″ 300blk pistol dedicated for home defense. I saw this brace a few months ago on a video. It’s next on my must buy list. A Honey Badger pistol!!!!

  2. I think it is going the opposite way. As these braces become better stocks, any need to aquire a stamped SBR will be mitigated. It’s not just cost, it’s the NFA rules on storage, transport and transfer that pain. I’d far rather have something 90% as good as an SBR for that role without the stamp and the pain, than an SBR, and I don’t think I’m alone.

    I travel through 2-3 states per day, (tri state area) making an SBR for a car gun a no go. If I’m not packing it, it’s a toy. What’s the point in an SBR in the safe when what I need is a good little carbine in the truck?

    I keep hearing about how this tax stamp thing isn’t a thing from gun writers. I’m telling you, it’s a big deal to lots of us for reasons practical, economic, private and principled.

    A pistol with a good brace is BETTER than the vaunted SBR for most of us for very good reasons. Barring a repeal of the NFA or removal of SBRs from it, I predict pistols with braces will outsell SBRs forever.

    • I agree, a pistol with a brace is cheaper and easier than a proper SBR. What I’m questioning is how much that convenience is worth. It’s definitely worth the $250 SB asks for this stock, but if it was a $500 part would the math still be the same?

      • I think for me and many others the question isn’t price, it’s NFA rules. The utility of a little carbine is indisputable, the impact of NFA rules can vary by location, profession and preference. For me, a weapon of this type that can’t freely cross state lines has little utility. Given that a proper brace on a pistol delivers most of the utility of an SBR, with none of the downsides, I’d absolutely pay more for the pistol than the SBR. YMMV, but I have to think there are an awful lot of people for whom one or more of the NFA rules and hurdles are a deal breaker, especially when it yields only marginal gains over the non-NFA weapon.

        My objection is mostly to the camp that treats these braced pistols as vastly inferior SBRs and questions why anyone would have one other than being cheap or unserious. They have some real and major advantages over true SBRs for lots of people and purposes. I guess I’d just like to see them accorded a little respect.

      • There’s around 27 million people in CA who can only look at an SBR as forbidden fruit. The brace is the only option, for now.

    • Amen to that. If the original ‘open letter’ had never come out, I wouldn’t have ANY SBRs.

    • I agree, In fact if these braces had come out a few years earlier I wouldn’t have 3 SBR’s.

      I have read many write something like “just do it right and get a Stamp”. I’m still waiting for my most recently form 1 from last June. It’s stupid for a multitude of reasons.

      I don’t care if it is a “gray area” or “loophole”, F the ATF & NFA!

    • and “I’m proud to jump through arbitrary unconstitutional hoops in order to exercise a fundamental right, because I’m a law abiding citizen. Not because I’m an elitist with buyer’s remorse… honest…. I swear.”

  3. Nick, thanks for this review, I’ve been interested in the exact setup that you have in 300BLK. I notice that in your picture, your cheek weld appears to be right at the junction between the mounting bracket piece of the brace and the sliding tube. Not that 300 is a beast, but do you notice much discomfort during recoil?

  4. The MPX PSB is marketed for the MCX. That’s why there are no complaints on its fit on the MCX.
    From SB Tactical:
    “The MPX PSB is an innovative, 3-position adjustable Pistol Stabilizing Brace® dimensioned to fit the receiver cuts of the SIG SAUER SIG MPX and SIG MCX. Ships as a complete assembly, ready to install, including an M1913 receiver saddle.”

      • The MPX PSB is for Sig MCX and MPX only. Most other AR15s have buffer tubes but since the MCX and MPX line are gas piston operated, they don’t have buffer tubes. The only difference between a MCX pistol and MCX SBR is the stock.
        That’s why I’m buying an MCX pistol in .300 BLK. Why buy a SBR and wait? Buy the pistol then if you want a SBR, submit the paper work and plunk down the fee.
        Thankfully Washington State fixed the law on creating a SBR because the previous language caused the ATF to deny applications for creating a SBR.

        • I understand this particular brace is fornthe MPX. They also make this brace, with the shortened buffer tube, for AR15 pistols. The military arms channel was the first to review it over a month ago. Fwiw.

  5. It appears the crowd is with me on this one. I suspected I wasn’t the only one who had issues with the NFA rules on SBRs. Frankly, if these braced pistols didn’t exist as a legal option I’d have to suffice with some other weapon to fill this role, as I did before them, because my situation and needs render an actual SBR prohibitively restricted.

  6. LOL! Third photo down looks just like one of the made up toy guns in the post “CapArms Question of the Day: Will Guns Ever Be “Normal” Again?”

  7. AK??
    Love the CA arm brace on my C39v2 pistol.
    It was awesome w a single point sling, but the brace was a game changer.
    An adjustable brace would just be sprinkles on top of that.

    And for the nay-sayer replys to the recent AR/AK Pistol articles here (&TFB)…
    Ya don’t get what ya don’t get. These pistols are a blast.
    Range toy rating- 5/5
    Grin factor- 5/5
    AK ammo cost- 4/5
    AR ammo cost- 3/5
    CQCb rating-5/5 (pure theory on my part; but <100yds it's really a moot point)

  8. You know of course that now that this can be more “easily” concealed, the ATF will find a way to ban it too.

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