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8 thoughts on “Well that would suck.”

  1. All too often I see silencers mounted on barrels with no verification of their co-linearity before firing a shot. Sometimes, people get lucky. Sometimes, they don’t.

    There are lots of people who like to take shortcuts when working on guns. Sometimes they learn why gunsmiths have large investments in tooling – tooling that many amateurs not only don’t understand how to use, but tooling that some people don’t even apprehend the reason for existing. A check rod, which costs about $65+, slipped down a cleaned barrel would have shown the potential for a baffle strike here.

    One meta-issue that leads to this result is a failure to understand and appreciate the mathematics involved. The issue of “will it strike or not?” is really just a trigonometry problem. We have only “X” so much annular clearance around a bullet as it leaves the front end cap of a suppressor. OK, so how to we insure that the bullet is within that annular clearance? We have to work backwards and reckon the tolerances for co-linearity of the muzzle thread pitch diameter, perpendicularity of the alignment shoulder, etc. These are small (typically 0.002″), and get smaller the longer the suppressor that is used.

    What some people learn the hard way (as here) is that some barrels that are threaded for mounting a muzzle brake are not within the tolerances necessary for mounting a suppressor. Use of a check rod would have revealed this.

    Reply
    • “…All too often I see silencers mounted on barrels with no verification of their co-linearity before firing a shot….”

      That obviously is a well-used suppressor, which tells me this likely occurred at the result of something out of the ordinary and not the operator error that you so pontifically ASS-u-Me.

      Then again, that trouser leg is from a Marine desert MCCUU, … so there’s that.

      Reply
  2. Is this government-registered device now scrap? Or can the user send it to a gunsmith (suppressorsmith?) or manufacturer for a rebuild without a new $200 tax and NFA rigamarole?

    Reply
    • This type of repair would be a major overhaul and the ATF would want a little something to wet their beak.

      The cost of this repair alone would probably be cost prohibitive as it’s most likely destroyed the baffle stack and not just the end cap. Might as well get a new can.

      Reply
  3. I built two Form 1 suppressors and deliberately built slop into the bore diameter just for that reason, to avoid a baffle strike. Since all I have is a drill press, getting the baffle holes EXACTLY centered, even when center punched, was iffy for me, I made certain to oversized the holes.
    The 5.56 suppressor bore is 5/16″ (.3125″, but with filing to remove burrs ended up at .337″) and gives me .0565″ clearance around the projectile. Also since some of the baffle holes were a tad off-center, filing them out corrected it.
    The 30 Caliber suppressor was drilled to 3/8″ (.375″, but measures .386″) and gives me .039″ clearance.
    The suppressor bore diameter is not that critical, the 30 Caliber suppressor works just fine on a .22 caliber rifle.
    How did I verify the suppressor bore was centered to the rifle bore? I eyeballed it from the breech end of the rifle barrel. If I saw anything other than a circle of daylight then more work was needed on a baffle before final assembly.
    In fact, the 30 Caliber may even work on my 350 Legend, but I’m not going to risk it. The clearance would be only .0165″ around the projectile.

    P.S. Do not use a crush washer with a direct thread suppressor.

    Reply

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