• Part 1 covers the parts, tools, and steps required for building a suppressor.
  • Click here for Part 2: How to E-File ATF Form 1 to get paperwork instructions.
  • You must file Form 1 and receive approval from the ATF before building a suppressor.

NOTICE: All parts sold by retailers and described herein are not fabricated nor sold as suppressors, suppressor components, or sound-damping firearm devices. Solvent traps are intended to be used only as firearm cleaning accessories. Constructions described herein must be made by the end-user within the confines of the law.

Suppressors are over-priced, and the ATF is way too slow when it comes to processing Form 4 applications for ownership. One year’s wait to buy a can? No thank you. And that Gemtech or Surefire (yeah, the one with the $1,000 price tag) that you’ve been drooling over? It ain’t worth that much, Jack. It certainly isn’t worth waiting 12 to 18 months just to take the damn thing home. No worries. You can reliably build your own suppressor with simple tools and parts, and you can get the ATF to do your bidding and process your application to build a suppressor in about two to three weeks.

A properly homemade suppressor will perform just as well as or exceed a retail-purchased silencer. We’re not talking about Wix oil filters or Chinese “fuel filters” in this guide. We’re not covering some gimmick that could blow up on you or land you in prison. Part two of this project will cover how to legally finish this project by filing some electronic paperwork and fingerprints with the ATF. But that’s not as exciting, so let’s focus on the fun part. Here’s how to build a quality, homemade suppressor with little to no knowledge, and just a few basic parts available from various retailers.

How a Suppressor Works

It’s important to know how a suppressor works first. A big part of this project involves cutting or drilling the right components to ensure your homemade suppressor provides adequate noise reduction without exploding or failing.

The inside of a suppressor. The baffles and chambers attenuate noise by reducing the velocity of the expanding gasses produced at the muzzle of the firearm.

A suppressor’s job is relatively simple: Capture the gasses exiting the muzzle of your gun, and contain them long enough to slow them down, reducing energy and sound. The suppressor does this by creating turbulence in the gas flow. That turbulence is made by forcing the gas into small pockets, cones, and cavities. These are created with baffles. The longer all that gas has to expand and slow down before exiting the suppressor, the quieter the gunshot will be.

Now you know the basics. It really is that simple. Onto the construction part. A suppressor’s made with three components:

  1. The tube or “can”, which contains the baffles.
  2. The baffles, which slow down the gas inside the tube.
  3. The end caps, which contain pressure and secure the suppressor to the muzzle.
    1. The baffles slow the gas down, creating all that turbulence and reducing velocity. The tube and end caps contain the gas, preventing the explosion and sound inside from escaping. The energy your suppressor’s working to contain is incredibly high. That means your suppressor’s converting a lot of energy into a lot of heat. That means you need quality alloys like stainless steel, high-grade aluminum, and titanium. That leads us to the first section of the build itself:

      Building A Suppressor: Materials Required

  • Metal Tubing
  • End Caps
  • Baffles
  • Adapter (if not directly threading to muzzle)

Option 1: Buy Material from Scratch

Stainless steel and 7000-series aluminum work well for making your own tubes, baffles, and end caps, and basic 4000-series carbon steel provides an affordable alternative. Steel is heavy, so many builders combine these two alloys and some use titanium if they have the right equipment to cut and drill it. If you opt to buy the tube yourself then you’ll need tubing with a minimum wall thickness of .065″ for centerfire rifle cartridges like 5.56 NATO and .308 Winchester. If you’re shooting a magnum rifle or big rounds like .338 Lapua, minimum wall thickness jumps to 0.1″.

Option 2: Buy Solvent Trap Components and Fabricate Them

If you’ve ever heard of the 80% lower for the AR-15 or “ghost guns”, as the media calls them, then you’ll find the concept of the solvent trap relatable: Solvent traps are normally used as heavy-duty cleaning accessories for your rifle or pistol. Traps thread to the muzzle of a firearm with a tube and end cap. Inside, they often come with a series of cups and filters (also called “cones”) to capture those poisonous and corrosive solvents and cleaning chemicals. Conveniently, these internal filters and cups are often made from high-grade aluminum, stainless steel, or titanium to resist corrosion. These “internals” are also perfect for cutting and drilling some improvised suppressor baffles. Take a look at the example below:

This Quiet Bore solvent trap kit is threaded for the typical 1/2×28″ 5.56 NATO barrel, and 5/8×24″ .30-caliber barrels. Thread adapters are available for other thread sizes.

Solvent traps like the 5.56/.30-Cal Kit pictured above include all the components you would need to cut and drill raw material and modify the trap to instead function as a suppressor (once you’ve filed the appropriate ATF paperwork, of course):

  • Stainless steel (SS), Aluminum (Al) or titanium (Ti) tube.
  • Stainless steel (SS), Aluminum (Al) or titanium (Ti) solvent cups.
  • Spacers, to separate and stack the cups if they aren’t “skirted”.
  • Threaded and sealed end cap to prevent chemical spillage.
  • Threaded open end cap for attaching to muzzle.

The only work you would need to do to the solvent trap above involves drilling pass-through holes in the solvent cups, turning them into baffles that a bullet can pass through, and “clipping” those holes. Clipping involves cutting small ports into the pass-through holes to create additional turbulence and improve performance. It’s incredibly important the diameter and location of the holes you drill be precise. If the holes are too wide, the suppressor won’t capture and dissipate all that pressure (and sound) effectively. But drilling holes with tight tolerances means they need to be incredibly precise, lest you wind up with an exploding suppressor because your first bullet down the tube struck a baffle or ruptured the tube. So, how do you make precisely machined holes? Many machinists and hobbyists use a lathe or drill press. Even without any tools like that, you can simply use a machining jig like the one below, which many solvent trap manufacturers provide alongside their various cones:

The drilling jig ensures the baffles you drill for your homemade suppressor are safe and effective.

A jig includes a small centering fixture to be clamped in a vise, and a plate with a drill bushing for the cones’ drill bit. This jig setup allows you to automatically find the center of the cone or cup to drill the pass-through hole centered perfectly. A drill press or even a hand drill can be used with a bushing-equipped jig. All you need to do is secure the cup and jig assembly together with screws. Then drill through the baffle via the jig with the appropriately sized drill bit.

The drilling jig plate is usually secured to the baffle jig with Allen-head bolts. Once secured in a vise, simply drill through the baffle’s drill bushing with a hand drill or drill press.

Since the jig controls the bit’s position, all you need to do is control the drill while each hole is completed.

Drilling The Baffles: Drill Bit Sizes vs. Caliber

Use the bit size list below to drill the appropriate diameter pass-through holes in your solvent trap’s cones or cups. If using your suppressor on various weapons (like a 5.56 NATO rifle and a 300 BLK pistol), always pick the bit size based on the largest caliber your suppressor will be used on.

  • .22-Cal: 9/32″
  • .30-Cal: 3/8″
  • 9mm: 27/64″
  • .40 S&W: 15/32″
  • .45 ACP: 33/64″
  • .450 Bush: 17/32″
  • .458 SOCOM: 17/32″
  • 6.5 Grendel: 21/64″
  • 6.5 Creedmoor: 21/64″
  • .338 Lapua: 13/32″
  • .50 Beowulf: 9/16″

Before you go drilling holes into some solvent trap cups, you need to figure out which design works best for your chosen cartridge. The type of ammo you’re trying to suppress — centerfire or rimfire, supersonic or subsonic, rifle or handgun — will largely dictate what types of cones or cups you use in your suppressor. Let’s review the common types of internals most often sold for solvent traps, and what applications they’re best used for.

Available Types of Cups and Cones

Straight Cone (60- or 50-degree angle)

The straight cone is most effective in centerfire rifles shooting high-velocity supersonic ammunition, with speeds approaching 2,500 to 3,000 feet per second. These are used most often for calibers like 5.56 NATO, .308 Winchester, .300 Win Mag, and similar supersonic .22 and .30-caliber cartridges. Straight cones are most often sold in 50- and 60-degree variants. A general consensus among experienced suppressor builder says 60-degree cones work best for higher velocities, while 50-degree cones work better for intermediate velocities above 1,125 feet per second but below 2,500 feet per second.

Radial Cone

Radial cones are effective “hybrids” most often used for both centerfire rifle rounds and subsonic pistol or carbine rounds. Many commercial suppressor manufacturers use baffles with a similar radial or curved design. These are most often used on guns that can fire both supersonic and subsonic ammo, and are favored for 300 Blackout and 9mm Parabellum cartridges.

Stepped Cone

Stepped cones are often called “Aztec” cones for their unique stepped shape. These cones have been reported to produce lower pitches and overall tones when used to suppress either subsonic or slower supersonic cartridges. The builders’ theory is that the cone’s stepped design works to induce greater turbulence to the gas flow. Other feedback says high-velocity cartridges do not benefit so much from this design, while slower cartridges can see a small increase in performance. Stepped cones are often similar in their overall length and angle as straight cones, providing a 50- to 60-degree slope.

K-Cups

K-cups or K-baffles represent an older design. They stack directly atop each other and provide excellent performance for handguns, pistol cartridges, and exclusively subsonic rounds. If you’re building a setup meant for a 9mm handgun, .22 LR, or 300 Blackout shooting only subsonic loads, the K-cup stack is a top choice. These internals can also be the most difficult to machine since they require additional machining beyond simply drilling pass-through holes and basic clips, so they may not be favored for first-time builders or those without a milling machine or lathe.

Freeze Plug-style Cups

These “freeze plug”-type cups are the most affordable, arguably the simplest, they’re highly stackable, and they’re versatile. They’re the “OGs” of the form 1 suppressor world and were used long before manufacturers began producing newer styles like the options listed above. They can generally be drilled for any caliber up to .308 Winchester and provide mild to good performance for a wide variety of supersonic and subsonic loads. Their performance will be poorer compared to a by-design conical or radial setup. Before different options became available commercially, the freeze plug was the top choice for most Form 1 suppressor builders.

Skirted vs. Skirtless Cones

You can find many of the cones listed above with a skirt, or pre-fabricated spacer machined directly into the cone itself. This eliminates the need to buy your own spacers or cut them from raw tubing. There are various other types of internals made for form 1 builds, though the options listed above are the most popular and comprise a majority of configurations for most calibers, including both centerfire and rimfire rifles and pistols.

Achieving the Proper Setup

The two most important factors that dictate the performance of your suppressor are the type of cone/baffle you use, and the spacing or “stack” of your suppressor’s internals. That means figuring out the appropriate configuration for three parts: The blast chamber, the cone or cup spacing, and the distal chamber.

This schematic illustrates a typical .30-caliber form 1 suppressor build. It measures 7.8″ by 1.5″ and is suitable for any .308 rifle. It utilizes a 1.55″ blast chamber which places the first cone approximately 1″ off the face of the muzzle. All cones are straight and progressively spaced from 0.5″ down to 0.4″. The distal chamber is spaced so the opening of the end cap (which uses a radial cone-type exit) rests 0.4″ off the bottom of the last baffle, with volume for gas to expand before exiting the muzzle provided in the 0.55″ distance between the threaded portion of the tube and the bottom of the last baffle.

Blast Chamber. The blast chamber is the area inside the suppressor that resides immediately in front of the muzzle. The blast chamber absorbs the most heat and gas, and must be made from stainless-steel or titanium if the cartridge being fired is a supersonic centerfire. Supersonic cartridges require a blast chamber that is long enough to place the opening of the first baffle approximately 1″ to 2″ from the face of the muzzle. Subsonic cartridges require a small blast chamber, one that places the opening of the first baffle just 0.25″ to 0.5″ from the face of the muzzle.

Cone or Cup Spacing. Suppressor baffles (in our case, our cones or cups) can be spaced equidistant from one another. Or, they may use progressive spacing that starts off longer in distance and shortens as the baffles move away from the muzzle. Supersonic cartridges prefer progressive spacing, while subsonic cartridges tend to work best with equidistant spacing. Straight cones typically require at least 0.4″ to 0.5″ of spacing to allow gasses to flow between each cone. Radial cones can be spaced more closely, approaching 0.3″ to 0.4″ between each cone. Since freeze plugs come with skirts, their spacing is pre-determined.

Distal Chamber. The distal chamber is the final chamber in the suppressor, located between the last baffle and the end cap. General suppressor design and feedback from the build community says that most suppressors should contain a distal chamber length of at least 0.4″ to 0.8″ between the bottom of the last baffle and end cap. A longer distal chamber lowers the pitch and overall tone of the reported gunshot, reducing perceived sound levels and the signature “crack” of a supersonic cartridge.

Clipping The Baffles

Unfortunately, drilling the pass-through holes into your cones or cups, turning them into baffles with spacers, and stacking them in your tube isn’t going to provide the best sound reduction. A best practice that is effectively required to achieve the most decibel reduction, called “clipping”, must be done to each drilled baffle to ensure sufficient turbulence and disruption of laminar flow is achieved to reduce pressure and sound as much as possible. This illustration below shows how clipped baffles perform compared to un-clipped baffles:

The clips on each baffle induce greater turbulence by sheering gasses away from the next baffle’s pass-through hole. This increases the time the gas spends in the suppressor before exiting.

Thankfully, an effective clip is easy to achieve on the most popular cones with basic tools: Cut half the pass-through hole horizontally by a height that is one-third to one-half the diameter of the hole. The finished cut should look like this:

Once drilled and clipped, how well does a homemade suppressor work? Do these setups provide the level of sound suppression offered by a branded silencer you simply purchased from an FFL? Here’s a decent audio comparison. Credit goes to Youtube channel Slammin Hawgs for their recent upload. These guys constructed a suppressor exactly like the example shown in this guide under “Option 2” using a Quiet Bore kit, then they ran some 5.56 NATO through it:

Video courtesy of Slammin Hawgs

The shooter is capable of safely firing his bolt-action with no hearing protection. The Quiet Bore solvent trap, once fabricated and modified, manages to substantially mitigate the sound produced at the muzzle of this 5.56-chambered bolt gun. For an easy sound comparison, here’s popular shooter and instructor Colion Noir test-firing an AR un-suppressed and then with a typical off-the-shelf can of a similar size and diameter:

Video courtesy of Colion Noir

The homemade suppressor, especially when built from a modified solvent trap, can operate just as well as (and perhaps even better than) a comparable retail suppressor. This shouldn’t be surprising, though — options like the Quiet Bore kit use can accommodate a modified design similar to a popular suppressor designed by Advanced Armament Corp. Yes, that’s the same company that developed the suppressor-friendly .300 AAC Blackout cartridge for U.S special operations.

One of Advanced Armament Corp’s suppressors uses a baffle design that’s virtually identical to Quiet Bore’s kit.

Where to Buy

Where can I buy a decent kit?

Solvent trap kits aren’t regulated as firearms, so any retailer can sell the parts. It’s important to shop for a kit that won’t explode the first time you pull the trigger. Plenty of suspect kits exist on eBay, and plenty more are probably dangerous to use. Stay away from overseas sellers and places like Alibaba or Wish.com unless you want the ATF or customs knocking at your door. Yes, it has happened. As recently as November 2019, one individual in Chicago received a printed notice that his overseas oil filter/solvent trap kit was seized by Customs as a firearm. He was issued a court summons. Do not buy a solvent trap kit from an overseas vendor. A few online manufacturers, comprising mostly small U.S. operations and enthusiasts’ machine shops, produce solvent traps and parts that come with favorable reviews and won’t land you a visit from the feds.

How much does a solvent trap cost?

That depends on the caliber, length and size of the tube and storage cups, what types of cups you’ll use, and materials your suppressor will be made of (steel, aluminum, or titanium). Most turn-key solvent traps that include all the parts you need cost between $250 and $500. You can buy solvent traps that include only a tube and end caps with no cups or spacers. These usually cost between $130 and $250. You’ll also need to have your tube engraved with its serial number, the name and location of the manufacturer (that’s you), and the model name (if you created one), which typically costs $30 to $60. The tube and caps aren’t considered NFA items, so any machinist or fabricator can do the engraving.

Premium Vendors with “High-End” Kits

These manufacturers are the cream of the crop. If you want to build a suppressor that outperforms a retail-bought unit, weighs less, and is more compact even still, these are the top options. These high-end kits provide tuned solvent traps that convert into top-tier suppressors for virtually all calibers. These kits’ prices reflects their quality: Starting at around $250 and climb up to $500, these components sport features like quick-detach muzzle adapters, integrated blast chambers, high-grade titanium parts, custom end caps, and optional protective coatings.

Vendors with Complete “Mid-Grade” Kits

These manufacturers provide quality solvent traps made from less expensive stainless steel and aluminum. These kits provide good performance and suppression and often come in around the $150 to $300 price point, depending on size, number of cones or cups included, features, and specifications. These kits are favored by first-time builders or those who want a budget build that can handle some abuse.

Individual Parts for Piece-by-Piece Builds

If you want to design your solvent trap suppressor from the ground up and purchase all required components piecemeal, these manufacturers below are also worth checking out. In addition to the providers listed above, these makers produce custom-cut and threaded tubes, cups, end caps, muzzle adapters, and other components you may need to build your first F1 can.

Frequently Asked Questions

So the short-n’-sweet of this project is that you can buy a solvent trap for your rifle or pistol for much less than the cost of a Gemtech, SilencerCo, or AAC and perform some machining work to make your suppressor relatively easily, and with good performance and cost. You’ve questions, so it’s FAQ time.

Are solvent traps legal?

Yes. Solvent traps are 100% legal to own. The ATF has labelled solvent traps “firearm accessories.” That means it is not a controlled item under any federal gun law, and owning one doesn’t mean you need to file any ATF paperwork. Solvent traps, unmodified, are not considered NFA items like a suppressor.

Do I need an FFL or paperwork to buy a solvent trap?

No. Since the ATF has classified solvent traps as accessories, purchasing a kit is no different than buying any other commercial product online. The kit can be shipped directly to your home of record, and no FFL or other paperwork is required. We do not, however, recommend ever buying a solvent trap that has any cups or cones drilled. These parts could be considered suppressors on their own.

Do I need paperwork to build my suppressor?

Yes. Building a suppressor is like building a firearm at home. It’s legal under the Gun Control Act of 1968. However, a suppressor is also an NFA (National Firearms Act) item. That means you need to fill out paperwork for a background check with the ATF before you drill or cut anything. The paperwork is called Form 1: Application to Make and Register a Firearm. Along with this paperwork, you’ll need to submit a set of fingerprints on the FBI’s FD-258 fingerprint cards, along with a 2″ x 2″ passport-type photograph. We’ll be linking to a guide that shows you how to do all this digitally. Here are instructions on how to file Form 1.

What are some popular setups?

Many builders who favor “abusing” their suppressor builds or firing big-bore or magnum calibers tend to stick to stainless steel and titanium tubes and internals. Many applaud titanium for its ability to handle intermediate cartridges like 5.56 NATO, 300 Blackout, and .308 Winchester while providing a lightweight build. Stainless works best for those big-bore rifles and magnum rounds. If you’re looking for a “gold standard” set of guidelines for building a do-it-all suppressor that’s lightweight yet capable of handling bigger cartridges, stick with a titanium tube and titanium end cap, stainless steel muzzle adapter or quick-detach adapter, stainless steel blast chamber spacer and blast baffle, and titanium cones or cups with titanium spacers. This will constitute the most expensive setup, but it will also weigh the least while providing the greatest capability with virtually any type of cartridge.

Can I safely use aluminum for my build?

Yes, you can. Aluminum is generally only recommended for rimfire (.22-LR) and handgun cartridges, excluding magnum loads. Many builders say aluminum baffles work well with low-velocity rifle cartridges such as subsonic 300 BLK, too, and this has been proven in various community builds. Gunpowder and carbon fouling will eat away at uncoated aluminum and can cause pitting and tarnish, so cleaning should be performed if you build your silencer with aluminum cones and cups or an aluminum tube. Some builders also employ anodized coatings when choosing aluminum spacers and cones or cups.

Where can I get more information on build specifications, baffles, or machining?

Silencer Forum’s Silencersmithing Section provides dozens of resources, images, examples of completed builds, and information relating to sizing and spacing internals, compatibility, and cutting and drilling your cups or cones. The Form 1 Suppressor Boards is a private forum that also provides a myriad of information.

Click for part 2 of how to build a suppressor (filing the right paperwork).