I recently purchased a used Glock 17C for a reasonable price. I got it just as a novelty and possibly for Action Match shooting. Since I have been playing around with PCC and Open Division handguns with compensators I wanted to see what the Glock 17C could do. I was surprised how well the ports worked. I tried it with factory 115 gr and 9mm major load and did not notice a significant difference in compensation.

I was doing some night shooting and thought it would be cool to capture the flash from the vented ports in the slide and barrel. I shot a video in slow-mo with my phone. Then scrubbed to the frame with the muzzle flash and took a screen shot.


  • TheNotoriousIUD


  • alex waits

    I wonder how much pressure is coming out of those ports vs how much pressure is needed to actually compensate for muzzle rise.
    Time to flex my google-fu

    • PK

      For a typical 115gr load, you’re looking at somewhere in the neighborhood of 3-3.5kpsi at the ports. It depends on the exact load used.

    • jerry the geek

      Actually, people who shoot compensated pistols in competition (IPSC/USPSA) tend to use a fairly fast-burning powder so the necessary velocity is achieved by the time the bullet reaches the compensator. The “overpressure” then vents to top and sides, to reduce muzzle-flip.

      (This permits the muzzle to return to ‘zero’ quickly, resulting in split-times of as little as .15 – .18 seconds).

      I was getting velocities of over 1400fps witn a 115 grain bullet in .38 super, with perceived recoil that could be ignored during the stress of competition.

      Essentially, it doesn’t matter how much pressure exit the ports, in absolute terms. In relative terms, the amount of pressure is “ENOUGH”.

      Of course, you need a fully supported chamber to handle the pressure surge upon ignition.

      • The old gamer logic used to be light projectiles/slow propellants in Open, and heavy projectiles/fast propellants in Limited.

  • Mazryonh

    I can’t find the exact reason as to why the compensated versions of Glock handguns were discontinued by Glock. Maybe some government agency objected and Glock decided to scrap those lines instead of continuing civilian sales.

    • Beju

      LE agencies tend to prohibit them due to the risk of being temporarily blinded in low light settings (when most shootings happen). I’d guess that they didn’t sell well to self-defense market for the same reason, and that the competition market bought Glock 34/35s instead, and got aftermarket barrels if they wanted ported barrels or thread-on compensators.

      Low sales probably made the extra milling steps and inventory variation difficult to justify to the bean counters.

      • Mazryonh

        A good explanation. This blog entry’s photo certainly illustrates the blinding effect. But what I don’t understand is if the M16A2 rifle’s flash suppressor could also act like a compensator at the the same time, then why not fit something similar to handguns with threaded barrels and get both lower flash and lower muzzle flip at the same time?

        • Beju

          Given the extreme muzzle flash some SBRs have, I’d guess that M16A2 style muzzle devices on pistol caliber weapons would require at least an SMG length barrel to avoid blinding flash.

  • Pete Sheppard

    Imagine touching a round off in retention position. WHY I never liked comped guns for possible self-defense.

    • Nicholas C

      That’s not what this is for. At least that is not what I intend to use this for.

      • Pete Sheppard

        I understand. Because a proper comp really does reduce muzzle flit, they definitely have useful applications. šŸ™‚
        I tend to think in ‘What Ifs?’ Also, there was a time when comp carry guns got a lot of attention.

        • iksnilol

          I prefer a suppressor, does the same, makes it point better, win win.

          Good for comps and assassinations (which are surprisingly common in Norway).

          • B-Sabre

            Comps, or assassinations?

          • iksnilol


          • B-Sabre

            Good to know!

  • Gary Kirk

    The apocalypse is nigh.. You must shoot the demons directly in the face..

  • T Rex

    You point an important fact that many are unaware of about any Glock “C” pistol that became readily apparent during a night shooting course I participated in back in the 90’s. Out of around 30 shooters, two guys had the new compensated Glocks that we all thought were way cool until after dark duriing an ambient light only course when the two above average shooters suddenly had a difficult time seeing their tritium sights and the dimly illuminated target after the huge amber flash escaping from the top of the slide killed their night vision. Both guys borrowed uncompensated Glocks to finish the night course and learned a valuable lesson about why to never carry a compensated pistol for defensive/duty use.

  • MarcoPolo

    The 23C is even worse, at twilight the first shot is fine and everything and everyone is just a glowing purple splotch after that. I have shot the normal 23 and 23C back to back and have been unable to detect ANY difference in felt recoil or muzzle rise. The fireworks look cool though.

    • gunsandrockets

      I’ve also shot the 23 and 23C, and the difference in recoil and muzzle flip is dramatic.

      • T Rex

        Detectable? Yes. Dramatic? Bull$#it.

  • SpartanGears

    jack-o-lantern or two phoenix’s?

  • Nicholas C

    Sort of and no at the same time. According to the Media Rep at Glock:
    “Regarding the ā€œCā€ models, no they are not
    coming back. There have been a few left over that have been put out but
    there are not any more in production.”

  • ??

    All of the muzzle flash can be almost completely eliminated by the use of powders with a flash suppressant. Hodgdon Autocomp is one of those powders that works fantastic. https://www.youtube.com/watch?v=slPMhrNHnYI