Remember when Sig Sauer tried to market the MPX Carbine with a short barrel but fixed muzzle brake?


Yeah that didn’t fly with the ATF. Well I accidentally made my own. I was at the range comparing my Osprey 45 uppressed MPX against my friend Ian’s integrally suppressed AR-9.

That is a whole lot of can under there.


Both guns were shooting the same subsonic hand loads and sounded equally quiet. Ian’s AR-9 is not a traditional integrally suppressed gun, it does not have a ported barrel. It is a short barrel with a long suppressor welded onto the end. He wanted a single stamp gun.

I wanted to change out the piston in my Osprey to test another gun. When I tried to unscrew the retaining ring, I ended up unscrewing the blast chamber from the monocore baffle.

Silver lining is that I can clean my monocore baffle.

So I reassembled the Osprey45 but left the tube out and made a giant muzzle brake which you saw in the top photo.

I was able to reassemble the Osprey45 and used WD-40 to help remove the retaining ring and piston.


  • Jeffrey Smith

    I didn’t know the Osprey came apart to clean. Was that a malfunction or is it meant to come apart? I know from reading the manual it doesn’t mention disassembling it.

    • Ragged Hole

      Yes, it a pistol caliber, user-serviceable can. It needs to be cleaned and maintained. The centerfire can are the only ones with welded baffle stacks that do not come apart.

    • Nicholas C

      It can be taken apart but only by SilencerCo. Mine accidentally came apart. The tube that the piston sits inside and the retaining screws into is what screws into the baffles and holds the rear section in place.

      • wetcorps

        Why wouldn’t they make it disassemblable by the user?

        • GaryOlson

          Any boy can great his toys and rake them apart. Putting Humpty Osprey back together again is not a skill all boys have.

          • wetcorps

            Again, why would they design it like this? Supressors get very dirty, I don’t understand why they don’t make it user serviceable.

          • Flounder

            Most suppressors above .22 do not come apart for cleaning. I really cant explain why industry standards are what they are.

            For high pressure rifle rounds, cleaning suppressors isn’t needed, kinda, what happens is you end up blasting out the fouling as fast as you can put it in there.

            For .22 lr rounds you do generally clean it. And they often come apart for cleaning. But you can always use an ultrasonic or something similar to clean a sealed can.

            The industry standard on pistol rounds is changing to lean more towards user serviceable. But currently it is solidly in the sealed side.

          • lawbob

            It’s the nature of the design, the way the parts are pressed together. Probably would require special tools and a user could mess it up pretty easily – unlike the round “stackable” baffles which are pretty much dumb proof.

  • B. Young

    What is that camo tape? It doesn’t sluff off when it gets hot?

    • Mystick

      I got some of the stuff from Wal-Mart that I actually burned myself grabbing once, it was that hot underneath. Stayed on solid, though. Gotta love materials science 😉

  • PersonCommenting

    Ive heard of similar problems with their QD mounts…

  • Spencedaddy

    Nicholas C, what red dot optic is that on your MPX?