Reader Tyler Capobres writes:

Before I get into the details of how to integrally suppress a shotgun, please check your state and local laws before attempting this project. Most states don’t allow this, so working on this project could potentially be considered a felony. My state has passed the Firearms Freedom Act, which allows me to build my own suppressors. So long as they stay in my possession, stay in my state, are never sold or traded, and are clearly stamped “Made in Idaho”, they’re fully legal via states’ rights under the Commerce Clause.

The project started because of my initial attraction to the show “Sons of Guns” and their unique builds. In one particular episode, the crew built an integrally suppress AK47. A suppressor reduces the speed of the gas escaping the barrel, which prevents the “crack” you hear when a gun is fired and you’re not wearing hearing protection. Integrally suppressing a gun is different from traditional suppressors, which thread onto the end of the barrel. An integrated suppressor is built into, or attached to, the barrel itself, which allows the rifle to maintain its accuracy, and prevents the rifle from becoming incredibly long and cumbersome.

While integrally suppressing a rifle can be complicated and dangerous without the right tools, I theorized that the same thing could be done with a shotgun, without complex machinery. Shotgun barrels have long been ported to aid shooters in reducing muzzle climb. As the gas escapes through the ported holes, pressure is put on the barrel opposite the direction of the escaping gas. This has a secondary effect of reducing the overall amount of gas exiting the end of the barrel.

Since most shotguns have a smooth bore, you can easily port the barrel without having to worry about damaging any rifling. You still need to make sure that any burs are removed from the barrel, because even the slightest blockage or hindrance to the slug or shot could cause a catastrophic failure.

For this project, I decided to drill five port holes in the top of the barrel, spaced out an inch apart from each other. I started 1.5 inches from the end of the barrel, and used diamond-tipped bits to drill the holes. It’s easiest if you start by drilling pilot holes with a smaller bit, before moving up to a larger size.

To avoid the risk of too much of the wad snagging, I chose to go with 1/8” diameter port holes. Make sure you remove the burs from both the outside and inside of the barrel before continuing. I then tested the idea using a thin, stainless steel cylinder.

(It’s important to note that initial test shots were done with the shotgun in a mount, rigged with a cord for remote firing. I was 30 feet away, behind a three-foot-thick berm.)


The last piece to this puzzle is the suppressor itself. You can use a system of baffles, but I chose to go with an empty steel cylinder for mine, to save on overall weight. You’ll want a steel cylinder that is at least 1/16-inch in thickness. The overall dimensions are personal preference, but I recommend making it long enough so the cylinder extends three inches past the first and last port holes. The larger the diameter of the suppressor, the more gas you can slow down before it exits the barrel.

If you go with a baffle system, you can reduce the overall diameter. For my suppressor, I chose a four-inch diameter tube, with a 10-inch length. I had a local machine shop weld a plate onto each end, and cut out a hole 1/16-inch larger than the outer diameter of the barrel, so it had enough wiggle room to be taken off without too much of a struggle.

To keep the incoming gases from escaping out the sides of the suppressor, I added a rubber grommet on each end. While firing the gun repeatedly, I noticed the suppressor had a tendency to creep forward and fall off, so I added a universal shotgun clamp with Picatinny rail to keep it from moving forward.

What started out as a shotgun that would normally be uncomfortable to shoot without hearing protection, became a new way to enjoy my old shotgun. Even using standard birdshot and buckshot, the suppressor reduced the sound level to the point it was no longer painful without hearing protection.

It isn’t as whisper quiet as suppressors are portrayed in movies, but it’s still a considerable accomplishment in terms of rethinking old ways of doing things. While this was a fun project, I’m sure it won’t be long before someone comes along and improves on my idea, and I look forward to the day that happens.


©2016 by Tyler Capobres,


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43 Responses to Making Your Own Integrally Suppressed Shotgun

    • Integral suppressors are a part of the barrel. Since the barrel was drilled to release the gasses and the can was placed over the barrel it can be considered integrally suppressed. If the suppressor is detachable it wouldn’t be considered an integrally suppressed barrel.

      • Yes after reading your explanation, I realized that you were correct. The suppressor has to be a part of the barrel to be considered integrally suppressed. Thank You for setting me correct. 🙂

  1. Is he implying that because of his state’s Firearm Freedom law he doesn’t have to go through the NFA process? I would bet the ATF has different ideas on that.

    • I clicked on the link for and the last blog post on there was from 2010.

      You’d think they’d be trumpeting the success stories from the rooftops if it were effective in the way we’d love it to be.

      I’d love to be able to make a suppressor and not have to bother the ATF about it. I’d even be willing to deal with only being allowed to keep it in my state. As a step towards further freedoms of course.

      However, I’m wondering if the state government would go toe-to-toe with the ATF in my defense once they came ’round to confiscate my homemade suppressor….

      • No jokes intended here.

        The only way to make the NFA go away is if you lot treat laws like this as gospel.

        You don’t have to do what they say is legal, but it’s best to simply not question them. Not even slightly.

        Alaska also has this law on the books and if you stay quite no one gives a shit. Non-compliance is the first step to repealing the NFA, just like it was for prohibition.

        • Until the NFA is repealed, the quickest way to prison is to broadcast that you’re violating it. Equating this with repealing Prohibition is rather ludicrous, you’d need to outfit 30% of the people with NFA-violating weapons and turn them loose every night to run amok in the city streets.

          Short of Revolution 2.0 we’re stuck with NFA. Too much invested, too many jobs reliant on enforcement and the like. Just like the ‘war on drugs’ – it accomplishes no good, it stops no one from getting high, it stops no one who is addicted, but there is too much money, too many gravy jobs, and too much power involved in the kabuki theatre.

    • No doubt in my mind the ATF has a different idea. Not only will the ATF claim that he did not pay for a tax stamp, they will also dream up something along the lines of “conspiracy to …” and portray his failure to pay a tax as a felony conspiracy or some such non-sense.

      I admire his courage. I wish him the best.

    • There has already been a test case in Montana. It failed. The ATF will arrest you and the minimum sentence is (I believe) 10 years.

  2. Well that’s interesting. Unless I move I can’t have even an ATF approved one in Illinois(btw he almost lost me on the Sons of Guns reference LOL)…

    • I keep telling ya, make that jump. It’s only a mile, right? You’ll feel so much better 🙂


      • Thanks for the support. A silencer is about 50th on my list of gun related purchases. If I can get a go fund me sca…er online deal going:)

  3. I’m convinced that suppressors cost as much as they do because the laws make the market so limited and the regulatory paperwork so oppressive for manufacturers.

    Heck, you can turn a fuel filter into a rifle suppressor with the right adapter bushing. If it weren’t a felony to screw one onto your barrel without a tax stamp (in Illinois it’s a felony, period), the market prices would come down dramatically.

    • That adapter for oil filter suppressors is deemed to be a suppressor in and of itself by the ATF.

      Manufacture or possession of one is illegal unless you give the ATF their 20 pieces of silver. The ones you can buy have a serial number on them and require a Form 4 to be transferred. It’s truly ridiculous.

      • So, a tiny steel cylinder with threads on both ends is “contraband”?

        Note that said steel cylinder (a thread adapter) is on the order of 1 inch long and 3/4 inch diameter.

        We really have to trumpet this from the Hollywood Hills and Manhattan High Rise buildings. (Both locations produce about 95% of all mass media — television and movies — distributed throughout the United States.)

        • “So, a tiny steel cylinder with threads on both ends is “contraband”?”

          Contraband no, controlled yes. The ATF treats it just like any full on suppressor because it’s the device that allows an oil filter to be readily attached to your gun for the purpose of suppressing the sound and flash. The adapters for like a 10/22 that make the barrel threaded are not controlled as threaded barrels are not controlled but the device that actually connects the gun to the oil filter is controlled and serialized.

          TTAG actually covered this a few years ago:

          While the story notes it’s “Probably not legal, but physically possible” to buy a similar device off of Amazon doing so is most certainly NOT legal in the eyes of the ATF. The original “Econo Can” adapter is a registered Class III item with the BATFE. Making your own, in BATFE eyes is the same thing as manufacturing a silencer. Simple possession of such an item along with a gun it could be threaded to could fall under ATF “constructive intent” rules too.

          As for the claims made in this story about the legality of state law vs BATFE regulation and the NFA… I wouldn’t bet on state law to hold up in court and I certainly don’t think any state is going to “go to bat” for a citizen that builds a suppressor in that state without an approved Form 1. If the BATFE decides to come down on this stuff and you’re involved and caught, prepare to get bent over and reamed sans any lube by both the ATF and the IRS.

    • That’s part of it yes. The market is only so big because of regulatory hurdles. The cops and the military only buy so many, and us civilians have to wait six months to acquire, and people like things in their hands “right now”, especially big-ticket items…

      However, if you look to New Zealand, where cans are unregulated, you can get a quality centerfire suppressor for under $200. Or even disposable ones for like $50.

  4. Hold on so it’s LEGAL to make SBRs and cans at home without messing with the ATF?

    That’s news to me.

  5. I sure hope all the following are true:
    (1) Someone mined iron ore in Idaho.
    (2) Someone extracted iron in Idaho from that iron ore.
    (3) Someone produced steel in Idaho from that iron.
    (4) Someone produced a 4-inch diameter steel tube in Idaho from that steel.
    (5) Mr. Capobres used that 4-inch diameter steel tube for his suppressor.
    (6) Mr. Capobres can prove all of the above.
    (7) Mr. Capobres can prove that taking that steel from the available steel supply did not reduce the steel supply. (Yes, I typed that exactly as I intended and you read it correctly.)

    If any of those statements are false, ATF will consider Mr. Capobres a tax evader and the United States Justice Department will consider him a criminal in violation of some felony. Furthermore, when he appeals his prosecution all the way to the U.S. Supreme Court on Tenth Amendment grounds, the Supreme Court will issue a summary judgement in favor of the government citing Supreme Court precedent in the case Wickard v. Fillburn. (That case extended federal interstate commerce regulatory authority to intrastate activity if intrastate activity affects the national supply of commodities.)

    Important note:

    Fedzilla’s subsequent prosecution (and the U.S. Supreme Court upholding the prosecution) will be in violation of the Second Amendment, Tenth Amendment, and our bedrock Presumption of Innocence (which requires that federal prosecutors PROVE that someone in another state produced Mr. Capobres’ steel tube rather than proving that someone made his steel tube in Idaho). But hey, if you are going to throw the Second Amendment under the bus, you might as well throw the Tenth Amendment and our bedrock Presumption of Innocence under the bus as well.

    • Not only will the IRS come after him, if he did indeed not file a Form 1 and get it approved, I suspect we’ll see this guy being charged under the NFA for making an unregistered silencer.

      The ATF/DOJ will win that argument all the way to the SCOTUS too. States rights are effectively dead at this time.

    • Nope, all that native-Idaho activity created value, and therefore has a price-depressive effect on surrounding economies through the indirect forces of supply & demand…therefore the federal government has dominion over every, single, last economic force or behavior, anywhere in America (Wickard v Filburn). Oh, and “human behavior is economic behavior” as the saying goes, so basically the feds have dominion over everyone’s logical (i.e. economic) actions.

    • I certainly hope ‘Tyler Capobres’ is a nome de plume and that he doesn’t actually believe that an adorable little protest law is actually going to protect him from Fedzilla’s rules, or reach.

      uncommon, I’m sure that would be their grounds for attack, if they actually gave two good flyin’s about this well-intentioned-joke state law. We both know they will just say, “irrelevant” and that’s that.

  6. That guy has bigger pair than mine, I admit.

    I wish him the very best of luck in the likely near future…

  7. I would like to see the author do this with FN’s new M240. Convert that bad boy to full auto!

  8. This would be illegal under the NFA. There is no interstate nexus requirement for a NFA violation so the state Firearms Freedom Act is irrelevant. Now if he was a felon, the ATF couldn’t do anything as there is no interstate nexus. Hope he has a good lawyer on retainer either way.

  9. There are several ways to quiet a shotgun, one of which has already been held by the ATF to not be a silencer: a very long barrel.

    Due to the paucity of powder in the typical shotgun load, the volume of a shotgun bore, and the rapidity of the burn of typical shotgun powders… all you need to do to achieve a ‘silenced’ shotgun is give the powder enough room to expand fully and lose pressure, which means that when the gas escapes from behind the wad, it will have a low velocity.

    How long does the barrel need to be? Eh, from seeing a old duffer who had done just this trick, I’d say between 5 and 6 feet of barrel length ahead of the chamber oughta do the trick. To accomplish this on a pump gun (eg 870), you’d just buy a second 870 barrel, hack off the back end of the second barrel from just forward of the forcing cone back. Get rid of the chamber/cone area. On the barrel that is mounted to the action, hack off the area where the screw-in choke is.

    Now weld the new, non-chambered barrel onto the shortened original barrel. You’ll need to do some work on the lathe or striking the barrels with a file to get the overall profiles to match. Get the ribs to match up and wha-la, you have a barrel that will make your typical low-brass trap loads sound pretty quiet. Yes, I’m making this sound trivial. It isn’t, but it can be done if you have the chops.

    Now, as to drilling holes through a shotgun barrel and not leaving burrs:

    You can either start the holes with a center drill/countersink bit, then drill it out about 0.005″ under-sized with a twist drill, then finish to size with a chucking reamer (which won’t leave burrs), OR… you could center/drill the holes, then get a flexi-hone and take a quick pass down the barrel with the hone, knocking off the burrs and making the bore smooth again.

    I prefer the center/drill-under/ream method.

    • There are a few companies that make such barrels. They have been used in the Twin Cities on urban hunts to cull deer populations.

      • Swinging a 6-foot barrel while bird hunting will get you the bonus of developing fantastic upper-body strength…

  10. “Knock, Knock”
    “Who’s there?”
    “ATF Who?”
    “ATF you are under arrest for an unregistered silencer”
    Yeah, they still call it that. It’s in the regs.


    The bad think at idaho here is it sthe 9th court that is very anti gun (see shall issue cases for shall issue california and hawai) and have ruled against the firearm act and the supreme court not want the case, thats my last stand so an very grey arena at moment to made an bye state craftet unregistered nfa item

  12. What’s sad is I’m try to login to atf eforms right now to pay for an sbr and a build my own silencer or two. Big surprise the website is down the day before there rules change. First it wouldn’t load. Now it says it’s down for maintenance every wednesday, which is high comedy because by my math today is tuesday. I guess they didn’t want my 800 bucks

    • Last day before the change to the new forms. The 13th (tomorrow) the new ATF41F goes into effect. Coincidentally that is also their scheduled maintenance day.
      I think the website is overloaded today with last minutes filings.

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