Why a Glock SBR?

I’m in the process of testing and comparing three different Glock handgun SBR enclosures. I asked my readers if they had specific questions about any of the enclosures.

From the top: Fab Defense KPOS, CAA RONI, Hera Triarii

From the top: Fab Defense KPOS, CAA RONI, Hera Triarii

Several of them asked “why SBR a Glock in the first place?”

Why a Glock / Handgun SBR?

  • Greater stability and control – four points of contact (both hands at two different points, cheek and shoulder) make for much faster, more accurate shots particularly as ranges increase.
  • Familiarity with the host pistol – we were already very familiar with the Glock’s controls, such as the magazine release, grip angle and grip size, and trigger reset and “feel.”
  • Magazine commonality – the idea of being able to feed a Glock SBR from the same magazines we carried every day seemed very attractive. If necessary, we could use the 33-round extended Glock mag in a pistol, too. The She-Shepherd and I train to fight together, and being able to pass off common mags in an incident is an advantage.
  • Small size and low weight – the first Glock SBR enclosure I purchased (the KPOS by Fab Defense) is smaller and lighter than any other SBR / PDW I own. Aside from a true pistol, it is also the most portable.
  • Conversion – a change to the ATF rules about “once a rifle, always a rifle” now means that you can carry an NFA-registered Glock as a pistol or as a short barrel rifle. This was not the case when I first started researching Glock SBRs. Of course, intra-state transport rules for NFA items still apply.

Why not a Glock / Handgun SBR?

Every firearm is a compromise. PDWs are governed more by “the purpose dictates the tool” than just about any other type of firearm, and there will always be trade offs.

PDWs all balance weight, size, capacity, effective range, velocity and caliber. It’s a delicate dance, usually along the lines of trading power and capacity for portability.

The SBR Glock is on the “portability” side of the spectrum. It is lighter, shorter, and smaller than all of my other PDWs, but it has some drawbacks as well.

The 4” stock barrel is much shorter than other pistol caliber carbines (PCC). This means lower velocity compared to longer-barreled PCCs like the Beretta Storm, Hi-Point Carbine or Kel-Tec SUB2000. Some have suggested buying a longer barrel, but I haven’t found any barrels that were long enough to justify the additional cost. It is not possible to use the Glock 17 barrel in a Glock 19 slide, so that option is out.

Depending on the enclosure, the SBR Glock may not be smaller than an AR pistol or AK47 SBR (the Hera Triarii, for example).

I am also concerned about reliability. Every enclosure we tested had a failure to eject, and while that may be more to the polymer rail and frame of a Glock, I think it’s worth considering reliability no matter what kind of handgun you consider converting to a carbine.


A pistol-to-carbine conversion offers additional points of contact, stability, familiarity and commonality if the “host” pistol is the same as a carry pistol. If you are trained to shoot multiple strings in a burst and zipper from the stomach / pelvic girdle up into the chest then you will find this is very easy to do with an enclosure.

The Glock SBR has additional benefits if you live in a country that sets limits on the calibers owned by citizens. Some countries also set limits on the quantity or type of firearms people can own, but do not regulate enclosures. The USA doesn’t have these restrictions, so my analysis does not take these factors under consideration.

Only you can determine if an SBR Glock (or other handgun) fits your needs and purposes. In the end, you’re going to make compromises somewhere, and as long as you have good reasons for making these trade-offs no one should doubt your decisions.

About the Author:

Short Barrel Shepherd Short Barrel Shepherd is a regular guy and works to make Web sites and mobile apps easier for people to use. He spends his free time attending fight-focused firearm, knife, and combatives training, motorcycling, writing, and playing games. His daily carry is a Glock 19 pistol and an AR15 .300 Blackout pistol in a backpack.
Filed in: Reviews Tags: , , ,

13 Comments on "Why a Glock SBR?"

Trackback | Comments RSS Feed

  1. David says:

    “Of course, intra-state transport rules for NFA items still apply.”

    I think you mean “interstate”. Also, FWIW, I believe you can interstate transport your Glock _as a pistol_ without filling out the ATF permission-to-travel form… you just couldn’t make it into an SBR out of state without one. Arguably, this is a feature and not a bug – you’re not taking your AR or AK SBR out of town without a form.

    Another point in favor of the Glock SBR is the wide variety of parts and accessories available in the after-market for Glocks.

  2. bond says:

    I’m afraid that’s not good info:

    The Glock is an NFA item once it’s entered into the database, enclosure or not you cannot transport it out of state without permission. The ATF doesn’t even know what enclosure you are using or care if it’s in one or not. They only care that the serial number matches an NFA item.

    • David says:

      Uh, no. I think you should consult this FAQ:

      This is a far more complex issue than you’re giving it credit for. The question is more “does leaving my Glock stock at home while I’m out of state count as me having functional control over it?”

      • Short Barrel Shepherd Short Barrel Shepherd says:

        David, to make sure I understand what you’re referencing — the post you linked to stated that if you remove the barrel of an SBR it’s legal to transport everything else out of state without prior written approval.

        Is this what you meant to link? Because a firearm without a barrel isn’t much use.

        • David says:

          That’s not quite what it says. It basically says your rifle stops being an SBR if you put a longer barrel on it. _Presumably_, your pistol stops being an SBR if you take the stock off it. Contact the BATFE if you want a formal opinion, I guess.

          • David says:

            Aha, here’s the ruling that makes this explicit: http://www.atf.gov/files/regulations-rulings/rulings/atf-rulings/atf-ruling-2011-4.pdf

            Check out the second to last holding. Actually, read the whole damn thing, it directly contradicts bond.

          • Short Barrel Shepherd Short Barrel Shepherd says:

            What you referenced was converting a pistol to a rifle and then back again, something that ended the prior ruling of “once a rifle, always a rifle.”

            You can turn your NFA registered Glock pistol into an SBR by putting it into an enclosure, and when you take it out it’s a pistol again. That’s the crux of the document you linked below.

            However, nowhere does it state that it removes the item from the NFA registry.

            It is my understanding that you can’t take an NFA item (pistol, rifle, suppressor, etc) out of state without the express prior written approval from the ATF.

  3. David says:

    “However, nowhere does it state that it removes the item from the NFA registry.”

    Just being in the registry is irrelevant. Read the BATFE FAQ above. If I turn my SBR-that-was-originally-a-rifle into a normal rifle, I am no longer obligated to comply with NFA requirements:

    Here’s another opinion letter that spells it out verbatim for you:

    Bottom of page 2.

    • Short Barrel Shepherd Short Barrel Shepherd says:

      We seem to be interpreting the letters differently.

      • David says:

        “Finally, if you place the long barrel on your registered SBR receiver (essentially converting the weapon TEMPORARILY from a SBR into a standard rifle), you may transport the long barreled weapon across State lines without completing the above-noted procedures and receiving permission from the NFA Branch.”

        No, you can’t take your pistol and the stock out of state together. But you can take JUST THE PISTOL or JUST THE RIFLE. Remember, what I originally said was:

        “I believe you can interstate transport your Glock _as a pistol_ without filling out the ATF permission-to-travel form… you just couldn’t make it into an SBR out of state without one.”

        That last letter I quoted confirms this.

  4. B R Kurtz B R Kurtz says:

    First I want to both thank and commend you for your efforts to explore the SBR field and specifically the Glock PDW. As you know the civilian PDW realm is only just in its infancy and of course little known to most shooters, even tactical shooters.

    I think we have to decide if the we want the Glock “enclosures” to produce a Mini SMG like weapon OR a Large Machine Pistol type end product. Looking solely from the outside; as much as I would hope otherwise, they seem to do neither well or certainly not yet as well as the alternatives. Again that’s the beauty of being in the birthing of this new concept–the potential is vast.

    I have wanted to like the Glock “enclosures” since they first appeared; but something has always kept me from making the leap, and your reports of reliability issues only confirms my concerns. I very much DO think there is a better system to be found. Personally, Id like to see a build similar to the Mauser Broomhandle, Browning High Power, or possibly the HK VP70. Each of those used a separate Butt Stock that could be quickly added when needed. Unfortunately the current slip on stocks do not seem to have grasped the original concept as much as Id like. Alternatively a system that allowed a folding wire type stock, much like the VZ61 Skorpion; which would allow the “pistol” to be carried in a holster, and used as a “pistol”, until the stock was needed. I am by no means an engineer; but the recent aftermarket grip adaptors along with the Gen 4 interchangeable grip backstraps, seems like a promising start.

    As to traveling out of state, well once we accept the NFA restrictions, the beauty of the Glock pistols is that they remain a great bargain. Having one as an NFA item does not preclude having a matching one as “just” a pistol. That same beauty echoes all the more by the complete familiarity of the weapon, either NFA or Pistol.


  5. CWP says:

    This coming from first hand experience: I have a Glock 20 enclosed in a host weapon platform and registered SBR. The accuracy issue has resulted in me regreting my decision to SBR the pistol. I should have gone for the AR glock lower and SBRd that. There is too much “play” in most of the enclosures in my experience. I have a red dot on top and have placed the laser bullet in the chamber. Even at close distances when the enclosure is pulled tight to the shoulder the red dots get crossed and are off by 2-3″ at 25 feet. This results in being way off target at 50 yrds. My decision was to mill the receiver and place a red dot on my glock and use a rest when hunting (waste of registered SBR). I know I can use the Endo or Mako buttstock but I usually have a rest when shooting. Maybe at a leter date. My set-up is a Glock 20 (10mm) with 9″ threaded Lone Wolf barrel with LWD Compensator and other upgrades. I hope this is helpful to those having the same want/need that I did. I short, If you want accuracy at long didtances, mount your sight to the slide not a host enclosure. Thanks!

  6. John Holmes says:

    Bout 3 years ago I tested the Roni, Hera, and the KPOS(gen1) eventually getting a gen 2. Roni and Hera were complicated pieces of crap. Only the KPOS was simple and reliable, though I thought the gen 2 was better at first, because no mods were needed to function ( studded back plate) . The KPOS Gen 2 didnt fit suppressor so very well. My the Gen 1 would work with the 17,19,34 and even the 37 and 38 GAP. So IMO , GEN 1 is the way to go (even with the stud you need to replace the backplate with). It’s smaller and lighter than a mini uzi.

Post a Comment