Saturday, May 4, 2013

A Reminder That Information Is Impossible To Prevent, Even If Manufacturing Is Illegal

Interesting, somewhat paranoid website: this guy builds adapters that screw onto the male threads on gun barrels (like 1/2"-28 for AR-15s) and have male threads that screw into common oil filters (like 3/4"-16 for some STP oil filters).  I gather that these create a noise suppressor (although probably not as good as one made for this purpose).

Doubtless, ATF will find some way to classify the adapter as a suppressor, with the all the corresponding paperwork.  But making this adapter is dead simple: anyone will a drill press, a piece of aluminum, a drill, and the appropriate taps and dies, can make these adapters.  Drill through the aluminum a big enough hole for the female threads, tap it, turn down the other end to a size that you can thread with a die.


  1. American Specialty Ammo has been selling these for some time and, yes, they sell them as NFA items.

    We actually were testing one out last weekend (a Type 07 manufacturer I know made one) with a variety of filters using a 9mm Colt subgun and found it to be very effective but with WIDE variation depending on the filter used and whether it was shot wet or dry. It was definitely hearing safe but we didn't do any head to head comparisons with actual commercial suppressors.

    My impression was that it is definitely "good enough" and given that these can be bought for less than the cost of any suppressor on the market including the NFA tax stamp and are pretty much indestructible and you don't need to worry about baffle strikes or damaging the tube which could destroy a conventional suppressor. I don't see them for pistol use as they greatly occlude the sights but they work well on a Colt 9mm platform.

  2. I'll second RevGreg's results. Widely variable, but generally decent noise suppression. Subsonic ammo, of course, makes a big difference, and I wouldn't expect one filter to keep it up for terribly long. One particular interesting aspect is that whereas a suppressor is often pretty easily identifiable, at least by those that know a thing or two about them, an oil filter or two in a truck merits no second glance (unless it has a conspicuous hole in the originally solid end, perhaps), and the thread adapter can fit unobtrusively in a tool box or somewhere.

  3. Speaking of information being impossible to prevent, apparently, it is now possible to print a plastic pistol with minimal metal components ( It's a brave new world!