The Glock Pistol as C-PDW: An Example

| December 5, 2016 | 13 Comments

This is a guest article from CR Williams, firearms instructor and author of several books on self-defense and firearms use (see our reviews of his book Facing the Active Shooter and Gunfighting, and Other Thoughts About Doing Violence). You can follow him at In Shadow In LightShepherd

There has recently been a fair amount of interest in some parts of the gun-world population about what I call the Civilian Personal Defense Weapon, C-PDW for short. In the chapter titled “Short Rifles and Long Pistols: The Quest for the ‘Civilian’ PDW” in Volume Four of my book series “Gunfighting, and Other Thoughts about Doing Violence” I define the C-PDW as:

…is a class of compact magazine­-fed semi­auto firearms that are more easily concealed and carried than carbines. C­-PDWs are supplements and enhancements to the normal concealed ­carry weapons that offer additional range, power, precision or a combination of those characteristics that when employed enhance the user’s ability to end fights more quickly and efficiently than common handguns.

A C-PDW can be anything from a short-barreled rifle or bullpup rifle to an AR pistol to a pistol-caliber-carbine or pistol version of a PCC to a stocked or, in the case I will be discussing here, what the Short Barrel Shepherd calls the “not-stock Glock” and what Gabe Suarez calls the “Glock PDW”.

Note that none of what you will see here is original work. Suarez specifically has done and is doing considerable development work on the Glock PDW. Everything I show you here is taken directly from what he and others have shown and discussed on the Warrior Talk website (where there is a thread specifically about this system) and on his blog/newsletter.

In a chapter in Volume Four, I showed an early-stage Proof Of Concept of the system consisting of an Endo stock adapter with a KAK Shockwave arm brace kit (arm brace and AR pistol buffer tube) attached to a Glock 22. That early effort has recently been superseded by this:



The slide of the G22 has been replaced with a Suarez International SI-335 slide which can accommodate .40 S&W, .357 Sig and 9mm barrels. (For now, the internals are from the Glock 22.) A titanium-nitride coated Glock 34 9mm barrel has been installed and a Trijicon RMR was moved from the G19 where it was to this gun. Suppressor sights, also made by SI, allow for co-witnessing. The Endo/Shockwave brace kit combination is the same as before but a folding-stock adapter has been added to allow for a smaller storage footprint and easier concealment. An inexpensive bungie sling has been added to allow me to go hands-free if desired or required. (The duct tape you see is holding an Allen wrench on that I can use to adjust the set of the Shockwave on the buffer in the field.)

Some of these components will remain only until I have better-quality replacements. Others will be changed to enhance operation and accuracy. I will go into more detail about these changes shortly.

Folded the total length of the GC-PDW is just at 14.5 inches. With the stock locked out the system is 22.25 inches long. This compares favorably to my AR pistol which is 26 inches with a 7.5” barrel with Noveske flash hider and is only a little longer than my 9mm Aero Survival Pistol which is just over 21” long.

Folded, the GC-PDW can be fired right-handed but not with the left and not with two hands. With the arm brace locked out both one and two-handed firing from the normal positions is possible:




The presence of the Endo and Shockwave shifts the balance of the weapon when firing this way resulting in some additional muzzle flip as shown here. This can be alleviated some when firing one-handed by proper use of the KAK Shockwave. Although it has attachment points for straps (also useful for sling attachment as you can see) the Shockwave is also made to provide support by friction with the arm. Tilting the gun a bit to the inside will help you get better contact and better management. Without straps it does not do as good a job of supporting the gun as the Sig arm brace but does work better than having no brace at all.

For those of us who have not yet or don’t want to pay the government 200.00 dollars, the real utility of having at least the buffer tube on the Endo adapter with or without the arm brace is the ability to add a third point of contact using the cheek index. (And let me be clear that without the NFA stamp you are not legally allowed to put any arm brace on your shoulder or mount a standard stock on the Endo.)


It won’t help with recoil management—you can see that in the photo—but for precision or long-range accuracy if offers an improvement in accuracy over an unsupported two-hand hold even with the RMR. Bursts of fire are not as easy because of the difference in balance and lack of friction against the skin but I believe with practice (and maybe some exercises to increase hand and forearm strength) this could be done in time. I have not worked enough with it to be sure of that at this time but I believe it is possible.

Accuracy is on par with any red-dot pistol. I have not run this system beyond ten yards yet but believe as I said that there will be better accuracy with the red dot using the cheek index made available in this configuration. Reliability is not what I want due primarily to the current installation of a .40 S&W extractor in a 9mm pistol. Once some of the internals are changed out I believe it will run as well as any Glock does.

Folded, the GC-PDW will fit in smaller bags than anything except the Masterpiece Arms 30DMG that I have previously written about here and here. It is also smaller (in width and height when folded) and lighter that the 30DMG. This makes it handier and more concealable that the MA is. One disadvantage for bag carry is the lack of external safety. This will require either assurance of the trigger being fully covered when it’s carried or carry without a round in the chamber. There are also at least two external safeties on the market that can be installed on Glocks. If I go this route I will use the Cominolli Custom safety.

As far as planned changes to the current configuration go: The off-brand single-point bungie sling will be replaced by (probably) a MagPul MS3 or MS4. This will give me an opportunity to check both one-point and two-point sling applications with this system. Some, perhaps most of the internals will be replaced with components that will enhance performance and reliability. I also want to acquire match-grade barrels in 9mm, .40 S&W and .357 Sig. (I am especially interested in seeing how the flat-shooting .357 Sig round works at range with this system.) Besides that I will be replacing the stock trigger with a flat trigger, either the Suarez International Patrol trigger or the Deux Ex Machina Gunfighter trigger. At some point after these changes I will probably look for a light and get a Comonolli thumb safety installed. Even before all of these changes are complete I am confident that the GC-PDW will find a place among other systems that cover the area of easily-concealable systems for use from across the room out to 100 or more yards—what I sometimes call the ‘Urban Truck Gun’ role.

Gabe Suarez says that the Glock PDW can replace any currently available SMG in the PDW role. In his and others hands I have no doubt of that. For myself and possibly for you the jury may still be out. But I see the potential. It is definitely there. And I will continue to work with this system to determine if it will work for me like I believe it will.

Consider investigating the possibilities yourself. You might like it.

About the Author:

CR Williams is the author of (so far) four non-fiction books: Three volumes of the ongoing "Gunfighting, and Other Thoughts about Doing Violence" series and "Facing the Active Shooter: Guidelines for the Armed Citizen Defender". He has also made entries into the fiction arena with recent releases of "Live Fire" and the first volume of the "An Even Break" series. He currently runs classes from either his home-base area in Central/South-Central Alabama or wherever anyone wants to host him for a class. An active and ongoing student of the fight in all its aspects, he continues to work toward his goal of making you the very best defender of life and loved ones that you can be.

13 Comments on "The Glock Pistol as C-PDW: An Example"

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  1. David Dominiecki says:

    Have you even considered the new Roni Micro or Roni stab with either a bone stock g19 or 17?

    Not the older enclosures offered by Roni or KPOS,but the latest one retailing for $225.

    • Short Barrel Shepherd Short Barrel Shepherd says:

      Hi there — can’t speak for CR, but after my experience with the RONI, KPOS, and Triarii I am not sure if any other enclosure product (regardless of manufacturer) is going to be able to overcome issues, because they all lock up with the polymer rail the same way. I’d be willing to give it a try on an evaluation unit and some various testing ammunition, but I spent a lot — a lot of money to come to my conclusion.

      Might be worth trying if someone else has a full-sized frame Glock in .40 S&W and above (which I don’t).

  2. Adam says:

    First I want to say I am a rifle refinisher and builder in Arizona and Gabe Suarez products are squared away and offers some of the best training available.I rub shoulders with former special forces and extremely intelligent men in the art of warefare and the firearms industry. I find that building it right the first time doesn’t require you to change it or dink around or “work in progress” as you change your mind. There should be no reason to change once you build as a civilian unless your philosophy or reasoning is fundamentally flawed. Buy once cry once…be patient…save until you can buy it and don’t be irresponsible because you have no patience and want it now. Trial and error. Shoot it, train with it, shot timer, if it works it works, if you realize you did a royal screw up then learn from your mistakes, move on, and DO MORE RESEARCH from top minds and performers in the industry to find what they have already done 15-20 years ago. We do not live in a different world or time. That is marketing nonsense.
    Uzi is an incredibly compact weapon system. It is heavy so recoil is now and follow up shots are incredibly fast and accurate. All other pistol caliber PDW is a compromise.

    I have shot so many SBRs from Sig MPX, MCX, Uzi, SCAR, AR in 5.56 and 300 blackout, AK platform, and HK that I wouldn’t compromise on a pistol with an “arm brace”. It is irresponsible and ridiculous to encourage people with less experience to do so and calls into question your intent on putting it on a Glock. I hope you don’t get caught shouldering it while you are training because I would call anyone a liar if they didn’t intend to shoulder it during an exchange of gunfire.
    The novice or experienced’s money is better spent getting in shape and training with their weapons, getting a nice set of tritium night sights and getting fast and accurate. Your life may depend on it.

    There is always more than one way to skin a cat but there are fewer fast and efficient ways to do it verses hokey. I appreciate the write up and demo but I wouldn’t trust my wife or son’s lives to that.

    I’d rather be honest then dead.

    • CR Williams says:

      “I find that building it right the first time doesn’t require you to change it or dink around or “work in progress” as you change your mind.”

      Some things really are a work in progress when they are being evaluated or experimented with as I am doing here. And some things you think are right the first time turn out not to be once you have some experience with them. When that happens you admit that and make the changes that make it work better.

      If you’ve always done everything right the first time you’re doing a whole lot better at it than I am and I envy you.

      I’m not trying to market this. I know Gabe is but that’s Gabe and not me. I personally was interested in looking at it and knew other people were so I wrote it up. As far as doing research, well, that’s what this is right now. I have benefited from what others have done so far with it and hope that others can benefit from what I’ve done here with it. Again, no more, no less.

      I agree with you that it’s best if you pay the money and get the stamp. Many will not, so I’ve offered my perspective on that.

      The Uzi is a fine system but many will not carry it because of the weight or because they would have to SBR it to carry it. The same is true of a lot of semi-auto subguns that could be used for bag guns in the US. You’re absolutely right about the arm brace being a less-than-ideal alternative. Fact is that lots of people will go with that before they go SBR, though. So I’ll try and help them do the best they can with that just like I would if they were running handguns and rifles.

      For now, what I say is it has potential and I’ll swap some more parts out. I don’t think it is as good as a true stocked pistol, though. And to repeat: While Gabe and some others can likely take one of these and replace an SMG with it, I’m not convinced I or others not at his level can. Yes, I think it can find a place in that up-to-100 or a little better yard category.

      It will be a while before it’s there, though, and I could be wrong thinking that it can. (Not like I haven’t been before.)Maybe I should have put that caveat into the article.

  3. van der lin says:

    so I have actually done this, like in the pic w/ the folding mechanism an all.

    it is lighter than any thing else you might carry in a bag, including super light custom built ARs, even with plastic receivers and trunciated receiver extensions with half lenght bolt carriers and 7″ barrels w/ CF handguard etc.

    it is way lighter than any uzi or other blowbaclk semi sub gun, epeically if you don’t have an old grandfathered one that fires from an open bolt. It also compares favorable to the recoil/weight ratios of PCCs being that it fires from a locked breech.

    I actually did this first w/ another SBR’d block, w/ a proper stock it really does fire faster on target than a guy can w/ the same pistol just held in the hands, definately a benefit at typical gunfight ranges. I find it worked best w/ the stock fully extended resting on pectoral basically shootingin an isoslese stance. basically it enables you to shoot a centerfire pistol both faster and more accrately than you could a 22, well maybe not quite as well when shooting 45, but in 9mm heck yeah.

    But ultimately the concept has some real problems:
    1. Compared to rifle chambered rifles: pistols are so inheretnly mechanically inaccurate and pistol cartridges are also, and pistol external ballistic are so poor, it is hardly worth carrying all the extra kit in terms of the benefits it gives you at range rather than just CCW’ing an auto or carrying a rifle chambeirng PDW. If you were to run towards gunfire, being able to strike at near the same distance as an active shooter likely armed with a rifle is a helluva benefit. Ideal woudl be for you to shoot from a rest on cover at a distance and pick the guy off, maybe without hime having even seen you.
    2. handgun terminal balistics are so poor, it is hardly worth carrying a bag gun over just concealing an auto on the body.
    3. W/o being able to shoulder it, firmly it is not such a help. An AR pistol etc is better w/ a “brace” that you do not shoulder b/c you can have all sort of other places you can grab firmly to gain more stability. Even if you could leaglly put a VFG on the non SBRd Glock’s dust cover, it is not a good idea; even if it were to be secure, it would cause flexion which might induce stoppages.

    Now if i lved in MN, for example, to where I could conceal carry it as an SBR w/a proper folding and telescoping butt that I could shoulder I might do so, in 9mm, since in that config you can shoot really fast and on target even without a forward grip for your offhand and the load out weight of it and a bunch of stick mags would be far lighter than anything else. But, I am just not seeing the benefit of carrying it as a bag gun w/o a real stock over just regular CCW’ing an auto and two or three extra magazines.

    Sure you coudl carry it assembled/foldes in teh bag, but this would be less accesible for regular self defense than when carried on your body. Or, you could carry it just the “not a stock assembly” in the bag and atach it if you found yourself near an active shooter, but it seems to me that one woudl take to long putting it in there and then secureing it with the pin.

    I am thinking that something like a regular CCWd Glock chambered in 22 TCU or a FN 5.7 pistol might be better just concealed on the body as they would be just as easy to shoot fast and accurate about as the glock w/ a butt stock but w/o all the added weight, bulk, complexity etc. Or, something like a Thompson Center Contender pistol w/ a scope to carry in a bag as a gun that you could move towards gunfire with to pick them off from a distance. As of yet, most single or copule mass shooters armed with rifles are only concerned about a possible person with a CCW pistol in their immidiate area, not about someone shooting them from a great distance prior to when LEO arrive on scene.

  4. CR Williams says:

    1. Compared to rifle chambered rifles: pistols are so inherently mechanically inaccurate and pistol cartridges are also, and pistol external ballistic are so poor, it is hardly worth carrying all the extra kit in terms of the benefits it gives you at range rather than just CCW’ing an auto or carrying a rifle chambering PDW.

    Pistols and pistol ammunition is no more or less “inherently” accurate than are rifles or rifle ammunition as long as we’re talking off-the-shelf systems. Lock pistol or rifle in a rest and as long as they function as designed you will get predictable performance from either one. The longer barrel on a rifle may provide better mechanical accuracy after a certain range is passed but until then, mechanically, it will be all the same.

    When you pick one up then the rifle becomes (most likely) more accurate because it allows a steadier hold than the pistol does. Sure, rifle ammunition goes faster out the barrel and flatter for farther out. Until you have to make the long shot though, it’s a moot point between them.

    2. handgun terminal balistics are so poor, it is hardly worth carrying a bag gun over just concealing an auto on the body.

    One of the benefits of the bag gun is that you could have a longer barrel on it (in this case, 5.31in vs. 4.01(G19) or 4.48 (G17) and/or add some weight to the system. This gets you some additional velocity and/or the ability to run hotter ammunition in the bag gun than you can comfortably fire from your carry gun or, if you wish, a more powerful caliber such as .357Sig or 10mm. You can also often set a larger-capacity magazine into the bag gun than you would in your carry gun.

    3. W/o being able to shoulder it, firmly it is not such a help. An AR pistol etc is better w/ a “brace” that you do not shoulder b/c you can have all sort of other places you can grab firmly to gain more stability. Even if you could legally put a VFG on the non SBRd Glock’s dust cover, it is not a good idea; even if it were to be secure, it would cause flexion which might induce stoppages.

    The point here is good. I describe the cheek index because that’s what most people that don’t go the SBR/stocked pistol route will use and I want to help them get the most out of it they can in that case. As far as the AR-P being better from having more to grab onto, I think the only real advantage with it is the weight. If the AR-P were the same weight as this Glock, for example, you’d have pretty much the same movement, maybe more given it’s a rifle round, when you fired it.

  5. van der lin says:

    you porbably already know all this sir, but to be clear for everyone:
    Longer barrel legth has nothign to do with mechanical accuracy; that is to say that longer barrels do not add mechanical accuracy, they only add velocity which can help the external ballistics at range. Actually, shorter barrels of a given diameter are relatively stiffer and should be more accureate, all other things being equal.

    handguns are less mechanically accurate than rifles, as fired in a mechanical rest with a remote trigger actuator, empirically. Of course by “hand gun” I am not referring to a TC or Bolt action pistol etc. Of course there are exceptions, but typically, pistols are in the 4-8 MOA, often much more, mechanically whereas rifles are a quarter of that typically. Pistols, of course, typially have floating barrels. But even weapons with fixed barrels, such as an MP5, are ~4-8 MOA due to the fact that pistol ammunito is not made with as much quality contorl for concentricty and other things since it would cost too much when rifle level accuracy is not desired by end users without making the ammo too expensive for what it is. Of course it is possible with specially loaded ammunition and a specially chambered weapon with a fixed barrel for a pistol chambered weapon to be as mechanically accurate as a rifle, but thatwould all be a theoretical custom creation.

    With an AR pistol w/ a brace, you can get three solid points of countact: cheek, grip and forearm; by levering the brace into your cheek by pressing the forearm and the pistol grip in opposite directions. You cannot do this with the NSGlock because the endo adapter in the grip hole has too much laterl flexion and you do not have a forearm to apply leverage to. The endo adapter does alright when used with a butt that can be pulled straight back into the shoulder, it is just that this it is theoretically illegal w/o an SBR stamp and in most parts of the country a guy cannot CCW an SBR in a bag. Admittdely, it is hard for a bystander at the range or at an active shooting to tell whether you are sholdeirng the NSG or just holding it near your shoulder to make a cheek weld.

    I think that the pistol bag gun concept has merit, but with some sort of arm brace actually being used as an arm brace.

  6. van der lin says:

    also, if one is going to carry someing in addition to the CCW pistol on the body and is looking for more size, capacity, range and stability, then why not a long barreled comp’d race gun that shoot really flat, (and some push ear plugs)? Seems to me that such a gun would be about about as fast on target as a stocked Glock, and faster than a NonStocked Glock you do not shoulder?

    • CR Williams says:

      Excellent points and food for thought indeed. Note that I expect that at short range you still get pretty much one-hole accuracy from most pistols. But I am talking short range here.

  7. CR Williams says:

    Forgot to add: 8 Minute Of Angle accuracy is sufficient to make hits on an average man’s torso at 100 yards. And a comp is on my list of things I want to work with, especially if I run any .357Sig down the road.

    • van der lin says:

      if you are thinkign about carrying a big comp’d gun in a bag then consider a 9×23 on a 10mm Glock. Lone wolf makes 9″ barrels, or 6.6″ threaded barrels. KKM can sell you up to a 7.3″ barrel in the chambering. The chambering is made to shoot flat and be compensated. underwood and double tap sell loadings for it. Loads for it are with slower burning powders well suited to rather long barrels &/or comps. In very short barrels, like standard length pistol barrels, it isn’t that great compared ot 357 Sig.

      W/o a doubt, it is the ultimate chambering for a big handgun type bag gun/PDW. JUST DONT” FORGET THE EARPLUGS!

      • CR Williams says:

        As if I didn’t already have enough other calibers on my contemplative plate. Sigh…

        I still believe that the cheek index can and will contribute to single-shot accuracy at the minimum, especially in the absence of a rest or support of some type.

  8. John Smith says:

    I bought a SBR stamp for a g19 gen 3. My experience is that all stocks added to a locked breech glock decrease reliability. With the common beliefs about limp wristing you would think a stock would improve reliability but I have proven the exact opposite with my 19. My experience across the board is browning type pistols function better than glocks suppressed. When I added a suppressor and a stock to my g19 it would barely run. I believe light recoil springs to be unsafe in a glock. The striker spring in a glock pulls against the recoil spring and will unlock the breech with a light recoil spring. KB

    The solution I came to was the mech tech conversion. The unit is rather heavy and the design of it precludes a barrel length shorter than 11″ which unfortunately move it away from the PDW concept. Its accuracy is vastly superior to a locked breech glock and the blowback action runs flawlessly suppressed or not. Trigger characteristics are maintained across EDC and SBR.

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