Diamondback’s New 5.7mm Pistol Is the 5.7mm You’ve Been Waiting For – SHOT Show 2020

For more information visit DiamondBackfirearms.com.

Accepts AR triggers? Check.

Accepts FN 5.7 mags? Check.

Under 4 pounds fully loaded? Check.

Includes SB pistol brace? Check.

As you can see, there’s plenty to love about Diamondback’s new AR-type pistol chambered in 5.7x28mm. We had the chance to take one for a spin when the company announced the DBX57BGB at SHOT Show 2020, and, needless to say, we were impressed.

It looks and feels like an AR-15, but the operating system is radically different. Rather than direct-impingement, the DBX57BGB uses a locked breech dual-gas piston system. We weren’t able to take one apart and inspect it, but gas piston systems, in general, are known for their reliability and durability. The one we shot this week didn’t jam or malfunction, and we didn’t notice anyone else experiencing any issues, either. (Check back soon for a full review!)

The operating system is different, but the controls will likely feel familiar. The DBX57BGB accepts AR triggers, safety selectors, and pistol grips so you can drop in your favorite AR controls and hit the range.

The lower receiver also accepts FN Five-seveN 20-round mags, so if you were an early adopter of this increasingly popular cartridge, you already have mags on hand. Diamondback also plans to release future models that are compatible with the new Ruger-57 magazines.

From the trigger controls to the included handstop to the side-charging handle, Diamondback’s new pistol is thoughtfully and practically designed.

The 8-inch barrel is long enough to optimize the 5.7x28mm, but short enough to maintain great maneuverability. The sub-16-inch barrel length means the DBX57BGB is classified as a pistol, so users will need to 1) shoot the firearm like a pistol, 2) use a pistol brace like the one provided, or 3) register this firearm as a short-barreled rifle.  

The gun is a pleasure to shoot. The super light-weight design helps keep the gun on target, and the recoil from the 5.7 is minimal. It measures only 16.9 inches with the brace folded and 25.4 inches with the brace extended, and we found it to be shootable in either configuration (though a sling would be ideal while shooting with the brace folded).  

This gun is tons of fun.

MSRP: $1,299. Check out all the specs below:

  • Action Type: Semi-Auto
  • Operating System: Locked Breech, Dual Gas Piston
  • Caliber: 5.7x28mm
  • Barrel Length: 8″
  • Barrel Muzzle Threads: 1/2-28 RH
  • Muzzle Device Included: DBX Muzzle Device
  • Sights Included: NONE
  • Handstop Kit Included: Magpul Handstop Kit
  • QD Sling Swivel Included: NONE
  • Magazine Qty Included: 1
  • Magazine Type: 20-round (FN Five-seveN® compatible)*
  • Brace Included: Rear Picatinny Mounted, Side-Folding
  • Rifling Twist Rate: 1:9″ RH
  • Trigger/Fire Control: Standard AR-15 “mil-spec”
  • Forend/Handguard: 6061 Aluminum, Hard Coat Anodized, M-Lok Compatible on left, right, & bottom
  • Grip: Magpul MOE-K
  • Frame/Body: 7075 Aluminum, Hard Coat Anodized
  • Overall Length (no brace): 16.1″
  • Overall Length (brace folded): 16.9″
  • Overall Length (brace extended): 25.4″
  • Overall Width (excluding controls, no brace): 1.25″
  • Overall Width (including charging handle, no brace): 1.75″
  • Overall Height (without sights): 7.3″
  • Weight (with empty magazine – no brace): 3.0 lb
  • Weight (with empty magazine & brace): 3.7 lb

For more information visit DiamondBackfirearms.com.

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About the author: Jordan Michaels has been reviewing firearm-related products for over six years and enjoying them for much longer. With family in Canada, he’s seen first hand how quickly the right to self-defense can be stripped from law-abiding citizens. He escaped that statist paradise at a young age, married a sixth-generation Texan, and currently lives in Tyler. Got a hot tip? Send him an email at jordan@gunsamerica.com.

{ 30 comments… add one }
  • Joseph G Rietdorf December 28, 2021, 11:48 pm

    Trying to compare the 5.7 x 28mm to a 9mm is apples and oranges. The ballistics are very different to begin with. I own three 9mm handguns and three 5.7 pistols. I reload for all of them. In my opinion, for defensive purposes, the 5.7 x 28mm wins hands down. But it all depends on the projectile chosen for this caliber. I cast my own 37 gr 10 bhn hollow points for my carry weapon. It provides enough pentatration with an explosive outcome @ 2000 + fps with a very controllable recoil for follow-up shots. Even considerably less than the 9mm.

  • Jon Sheman June 8, 2020, 5:10 am

    NATO picked the 5.7x28mm after much testing to replace the 9mm. Germany’s HK 4.6x30mm entrant lost and Germany through a fit and would not adopt throughout the whole thing into a NATO political breath holding.
    40 countries and many police forces international along with Secret Service use 5.7×28. Why if it is so bad ???compared to 9mm?

  • Lee January 22, 2020, 12:38 pm

    The shooter is not shouldering the weapon. It’s an 1/8 of an inch from his shoulder. He is cheeking the weapon… which is legal.

    • Neil January 23, 2020, 2:13 am

      Check the latest ATF ruling. Shouldering a pistol brace is once again legal.

      • Scott January 24, 2020, 5:23 pm

        What’s the link for that ruling?

  • C.W. January 21, 2020, 7:45 pm

    CMMG MK57 with delayed radial blowback is about the same price point. Might be a tad bit heavier. Glad to see another firearm chambered in 5.7 x 28 though.

  • John Saxtorph January 21, 2020, 6:49 pm

    Lets settle this once and for all, forget any and all bias reviews, advertisments, paid endorsements, and the ballistic gel tests where the 5.7 got it’s butt kicked. Just look at the math.
    Since the .40, 10mm, 357 mag, and 45 are vastly more powerful lets just compare the 5.7 to the century old 9mm. Here are the stats on both of their hottest loads in pistol barrels. 4″ for the 9mm and I’ll even give the 5.7 the advantage of it’s factory 4.8″ barrel. Bullets for comparison are the top of the line S4M and the buffalo bore 115gr. Even though the guys in the five and seven forums say they are not getting the advertised 2600 fps we will give them the full benifit of the doubt and assume the advertising is accurate despite the fact that people have recorded 2400-2500fps in their crono.
    —————–5.7mm S4M—-9mm
    Energy———-405ft/lbs—–500 ft/lbs—Advantage 9mm
    Momentum——-10lbs———23lbs—–Huge Advantage 9mm
    Frontal Area-.—-.0394——–.1007——Huge Advantage 9mm
    Sectional Density-.08———–.130—–Large Advantage 9mm
    Now forget the ultra high performance hard to find ammo and lets focus on the stuff you can buy over the counter at any halfway respectable local gun shop.
    9mm Carbon 115gr JHP and the SS195LF
    Energy————255ft/lbs——466ft/lbs—Large Advantage 9mm
    Momentum——— 7lbs———–22lbs—–Huge advangage 9mm
    Frontal Area——–.0394———.1007—–Huge advantage 9mm
    Sectional density—-.08———–.130——Large advantage 9mm
    By every mesurment we know of the 9mm is superior to the soft tissue performance of the 5.7×28, I have asked on many occasions for the 5.7 junkies to explain to me what magic energy somehow makes it more deadly and nobody can explain it to me, I wounder why
    Even the most hardcore 5.7 fan should understand why I am so skeptical of it’s “advantages” over conventional handgun rounds.
    If you do the same comparison with the 40, 10mm, 357 Sig or any other modern handgun round the comparison get REAL bad for the 5.7×28.
    Cheese demilitarized ammo, barely suitable for self defense, hardly affordable for target practice? Tnx, no.
    Make a modern red-dot and brace/stock (e.g. FAB Defense) ready striker fired pistol with hi-cap double-stack magazine, 6″ BBL in 7.62×25 Tokarev and you win the fortune. I predict bunch of hipsters unsuccessfully trying to trade their R57 for G19 by the end of the year. Another Ruger’s fail.

    • Beachhawk January 22, 2020, 12:03 am

      Thank you, John. Finally someone has injected some common sense and a little science into this dispute. The only people I hear defending 5.7 pistols are people who spent their hard earned money only to realize they bought a white elephant.

    • Brian Sullivan March 7, 2020, 1:27 pm

      I have a 5.7 for home defense. I am not a 5.7 freak, as I have plenty of other choices. This gun is excellent for defense with 30% less recoil, quicker follow up shots. Less penetration but quick to tumble in flesh, that’s what is was designed for. Yes, heavier grain projectiles will hit harder, but you cant argue that with a sucking chest wound. I would not want to shot with it, especially with LE only green tips.

      With the high muzzle velocity, it is an incredibly FLAT shooter, with very little drop at 50 even 100 yards. It is very accurate. The major point with the round was WEIGHT per 50 round mags in the P90. You can carry a crap load of ammo concealed in certain situations, which can’t be said for 45 ACP.

      • Mike Faust January 24, 2021, 10:21 pm

        I agree with Brian on this. It’s a special round. And effective for what it was designed for and WHO it was designed for. It was not originally designed for the civilian. So when it made it to our hands the ammo was neutered. At least the affordable stuff. The expensive “specialty” ammo is where it is at.
        I also find that a lot of people dislike what they don’t understand or can’t afford. In the gun world it’s mostly can’t afford. If the ammo is expensive and hard to find and the gun is same- then suddenly the G19 is the holy grail. (It’s not- trust me- it’s the Porsche 911 of the gun world- never changes, and you have to spend another 1000 bucks to make it right -I own two Glocks-and we are all suckers)
        John’s math is correct- but it stops at impact. The 5.7’s non ball ammo is quite interesting when it hits.
        His idea of a 7.62×25 Tokarev powered one of these would be awesome and I’d buy one for each hand. A very dangerous round that needs a modern updated platform. And with all the milsurp out there (at least for now) would be an interesting combo.
        As for DB making it- hopefully it works better than some of their other pistols.

  • JCitizen January 21, 2020, 2:49 pm

    I like my AR-57 just fine – I won’t trade 50 round capacity for this new toy – but maybe for customers in high cap restriction states, this would be the thing.

  • Will Drider January 21, 2020, 12:17 pm

    I like it, barrel length is a big plus for 5.7 asis the low weight for what’sin your hands. Price puts it in close competition with an above many similar category pistols. The 5.7 was designed as a potential replacement for the 9mm military applications but never went anywhere. So a comparison with the Stribog SP9 is fair IMHO and it has higher capacity and 1/3 cheaper.

    I think they should have come out with Ruger mag compatibility as the initial offering. FN FiveseveN guys most likely went to FN Product long ago. Rugers offering at a lower price ill bring in NEW users and that commonality will will drive more sales.

  • Tom E January 21, 2020, 9:48 am

    What’s the muzzle velocity?

    • Ej harbet January 21, 2020, 4:43 pm

      Darn good question seldom answered in too many articles. You dont have to chrono it,just give us factory figures or even others data. Velocity is everything with itty bitty bullets

  • Zupglick January 21, 2020, 9:30 am

    I’ll stick with a PS90.

  • Mike Ross January 21, 2020, 9:19 am

    I was all set to applaud you for this,

    “classified as a pistol, so users will need to 1) shoot the firearm like a pistol, 2) use a pistol brace like the one provided, or 3) register this firearm as a short-barreled rifle.”

    That’s exactly right, but then a little more scrolling revealed a picture of a guy using the brace as a rifle stock. As the BATF has said, occasional, incidental, contact with the shoulder is OK, but that picture shows deliberate use as a stock. Which could, depending on the mood at the BATF that day, be considered a redesign. With the BATF currently reviewing their position on pistol braces, with much input from anti-gun groups, taunting them might not be a good idea.

    • James January 21, 2020, 9:47 am

      Why in the world are WE doing the ATF’s BS job FOR them? I see too many people in the 2A community reprimanding others for the vague “rulings” the BATFE dictates down to us “common folk”. We need to ALL push back against their stupid rulings. We need to exercise our rights….and if that means shouldering a brace….then shoulder a brace. Don’t be an ATF lackey and criticize others for doing it. Do you agree with the ATF? Do you think the NFA is a good thing? I DO NOT. Full stop, the ATF needs defunded and dismantled…..along with the NFA. The 2A says nothing about these clowns or these blatant infringements being lawful.

      • JORGE GARCIA January 21, 2020, 11:14 am

        Please do not be offensive to clowns, comparing the ATF to clowns. I had one out to my sons birthday party and when he was done, he took off his costume and proved to me that he was a logical intelligent person making a living out of making kids laugh. on the other hand I had to deal with a couple of BATFE individuals a while back during the purchase of a shipped 22 to my FFL and I can guarantee you that without a shadow of a doubt, that these two idiots were no were near as intelligent as the only clown I have had the pleasure of speaking to.

      • Don January 21, 2020, 9:28 pm

        I too disagree with the NFA but will allow there should be some restrictions on full-auto weapons in this less than perfect world. However, controlling stocks on pistols (less easy to conceal) or keeping rifle barrels long enough (so they won’t get less powerful) is a foolish waste of a lot of taxpayer money. Good for Federal employment though.

        • Removed_C January 22, 2020, 1:06 pm

          Ya know what I love most about America? Even when your opinion is wrong, you’re still entitled to it.

    • Stephen Graham January 21, 2020, 2:45 pm

      Excellent point!

  • Brad Mottishaw January 21, 2020, 6:44 am

    Can this firearm utilize binary triggers used in the AR lowers such as the BFSIII, or the Echo?

    • johnnyraygun January 21, 2020, 12:58 pm

      I a would think so, just as changing a different AR caliber upper on binary trigger lower. I wold like to own one with a matching 57 pistol.

    • Dev January 27, 2020, 7:23 pm

      What are you guys talking about? Can you explain this a little better cuz I’ve never heard of it. Why cant you hold this gun up to your shoulder? How exactly are you supposed to shoot it otherwise and what is the stock for if you cant use it to shoot at the shoulder?

  • Ron Y January 21, 2020, 6:18 am

    I would not be publishing a picture of using a pistol brace against the shoulder. ATF rules are grey at best and only sporadic use is allowed unless one has the request stamp. An unsuspecting person could reasonably assume that this was an allowed constant method of firing, especially coming from Guns America. If I am wrong I apologize.

    • Higgs Boson January 21, 2020, 9:12 am

      Spot on. Glad to see someone else thought the same thing.

      • KEN January 22, 2020, 8:13 am

        True that on the shouldering pic. Does he have sbr paperwork? Will he be getting a visit from law enforcement?

        • Darren K. Buchanan January 25, 2020, 8:37 am

          Thought the same thing.

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