With an e-filed ATF Form 1 (the application to manufacture your own NFA item) taking only three to five weeks (ish) for approval these days, as compared to about nine months for a Form 4 (transfer of an existing NFA item), interest in building your own silencer has increased dramatically.
But what if you don’t have machining capability? Can you convert an existing, non-regulated product into a working suppressor? Let’s find out!
There are a handful of products that are readily converted into a firearm silencer, including solvent traps (see HERE), oil filter adapters (see HERE — and FYI I’m testing this next), and apparently “fule filters.” Whatever that is (and yes, that’s how it’s spelled).
Well, it’s this. Presumably “fule filter” is a typo, likely during a Chinese-to-English translation, of “fuel filter.” Obviously the intended purpose of this product is to use it on your vehicle to, like, catch and filter gasoline or something. Sure it is.
But first . . .
DISCLAIMER: I’m not a lawyer, I don’t play a lawyer on TV, and I didn’t stay at a Holiday Inn Express last night. Everything below represents the choices I made while navigating this process. Some err on the extra-cautious side — more cautious than most folks believe necessary — some are absolutely mandatory.
Please be sure to review the relevant laws, consult an NFA attorney, and do your own research related to federal and state restrictions and requirements before proceeding with creating your own NFA item. Calling the NFA laws non-trivial would be a massive understatement, so do not run afoul of them. The penalties for doing so are severe.
In my quest to be extra cautious, the first thing I did was file my ATF form for approval via the ATF’s eForms system. The Form 1 is not only payment of your tax stamp and registration of your to-be-built NFA item, it’s also your permission — upon approval only — to manufacture said NFA item. I chose to file my form and wait for approval before even buying the product.
In my mind doing it in this order eliminates my risk of possessing something the ATF might consider to be silencer parts before I’m approved to have such parts.
The second “abundance of caution” choice I made was to purchase from a U.S.-based company. While this “fule filter” could have been made abroad, it did not ship to me from abroad. I chose a company that ships from domestic inventory.
It’s my understanding that some of the folks who ordered these sorts of things off of the Wish.com or otherwise via Chinese retailers and then received visits from the ATF were, at least in part, accused of importing silencer components.
It’s also my understanding that none of them waited on an approved Form 1 before receiving their parts. Again, this isn’t a legal requirement assuming the parts are not legally silencer parts, but I chose to do this just in case an argument could be made, as it apparently has been, that they are either silencer parts or are intended to be silencer parts.
With Form 1 approval in hand, you are now the legal manufacturer of the silencer that you’re going to create. This means you must engrave all of the appropriate manufacturer markings onto it. Model name, serial number, caliber, your name or the name of your trust or business, and your city and state. This must match the information you provided on your Form 1.
NOTE: Complete the engraving before actually doing the necessary manufacturing to turn your “fule filter” into a firearm suppressor.
As you can see above, I’ve deemed this suppressor the POS9MM and have given it serial number POS9MM-1. As a co-owner of Black Collar Arms, which is an FFL 07 and SOT manufacturer and the actual purchaser of this $39 fuel filter, I registered it under the company name.
Turning a fuel filter into silencer is, in this case, simple and straightforward. See the end cap above, sitting between the aluminum tube and the aluminum monocore filter structure? Obviously it’s solid in order to capture the automotive fule inside of the filter baffles — much like a solvent trap.
Drill a hole through it and now it’s a silencer end cap. That monocore filter set is now a monocore suppressor baffle stack. Amazing!
Slide the tube over the baffle then thread on and tighten the end cap to lock it all down. I suppose the silicone fuel line they sent can go in the trash. Ready to rock!
Here’s the range test video:
I chose to purchase a — ahem — fuel filter that’s threaded 1/2×28. This is the typical thread pattern of .22 LR and 9mm suppressors, which I figured were appropriate calibers for use with an all-aluminum silencer. Centerfire rifle rounds were going to be beyond the capability of this material…though you know I tested it anyway.
With a fixed mount — in this case the threaded mount is integral to the monocore — it’s unlikely that my new suppressor would work on a semi-auto pistol that doesn’t have a fixed barrel (meaning nearly every 9mm pistol out there). Due to the suppressor’s light weight, though, it’s possible that it would work on some handguns even without a booster (“piston” / Nielsen Device). I intended to test this and brought a pistol to do that, but ended up blowing up my POS9MM before I had a chance.
Anyway, first up was testing the can with .22 LR. I threaded the POS9MM onto the end of a Radical Firearms 10/22 and went to town with both subsonic and supersonic ammo, testing the Franklin Armory 10/22 Binary Trigger at the same time.
I was highly impressed! My $39 (yes, you still have to pay your $200 tax stamp, so $239) fule filter suppressor absolutely holds its own against commercially-available .22 LR silencers. No question it wasn’t quite as quiet as the SilencerCo Switchback I had with me, but it was far closer than I could have ever expected and it’s fair to say it was super quiet.
Would I legitimately choose to purchase a $39 “fule filter,” pay my $200 tax, engrave it, and turn it into a cheap-o rimfire silencer? Abso-freakin’-lutely. The fact that I can file a Form 1 and be on the range using my suppressor within a month is huge. Not to mention a couple hundred bucks or more in savings as compared to a commercially-available silencer.
Switching over to a 9mm pistol caliber carbine with a 16-inch barrel, I was similarly impressed. I found the POS9MM to be on par with the GEMTECH Lunar 9 when the Lunar was in shorty configuration. Needless to say, this once again far exceeded my expectations.
That said, the Lunar 9 in shorty mode is designed to be as compact as physically possible while staying just this side of the “hearing safe” 140 dB threshold on most setups, so it isn’t particularly quiet in short configuration. With the Lunar 9 in its full length configuration, it was noticeably quieter than the POS9MM, but not by as big a margin as I would have guessed prior to testing.
Would I go through this process to create a 9mm PCC suppressor? Yeah, possibly. It doesn’t hold its own against “real” silencers (Form 4 silencers) from “real” companies as closely as it does on .22 LR, but it’s still a perfectly functional, legitimate suppressor and it should hold up perfectly well for many thousands of rounds of 9mm use.
What it will not hold up to, though, is centerfire rifle use. That’s no surprise. Aluminum — particularly what I assume is not the highest grade aluminum and it clearly isn’t hardcoat anodized — simply isn’t up to the task of dealing with the pressure, heat, and intense particulate blast of rifle rounds.
So naturally I put the POS9MM on the Brownells BRN-180S setup with its 10.5-inch barrel firing full-power .223 Remington. Bore erosion was dramatic after only 35 or so rounds. That supersonic particulate ate away the aluminum like mad.
Unfortunately that was the least of the POS9MM’s problems. Between the first and second baffles, the aluminum monocore began to stretch almost immediately. One or two shots in and gas was already leaking, violently between the end cap and the tube as the monocore had grown longer and the seal was broken.
And that’s not all that broke. At 35-ish rounds most of the monocore flew downrange, having separated at the stretch point between the first and second baffles.
The moral of the story here is clear: an aluminum “fule filter” turned suppressor isn’t going to hold up to centerfire rifle rounds. Stick to rimfire and pistol fodder.
Believe it or not I consider this to be a big success. For $39, a tax stamp, and only three to five weeks wait time one can have a great .22 LR suppressor and/or a decent 9mm suppressor with personalized markings. That’s hundreds of dollars and many months less than purchasing a typical silencer from a commercial silencer manufacturer.
Just don’t forget your fule filter silencer’s limitations.
• It is intentional that I didn’t link to the website I purchased this product from, as I’m somewhat hesitant to encourage or endorse this specific seller, product, or process.
• There is regulatory risk involved here. None of the above is legal advice, it’s simply what I did to navigate this process as safely and as legally as I knew how given the information I had at the time for the purposes of this post. Proceed at your own risk.
• Black Collar Arms, as an FFL 07 / SOT, files a Form 2 for this kind of stuff, not a Form 1. That changes nothing about the process other than, as a manufacturer, there is no $200 tax and approval is typically even faster.