JK Armament Solvent Trap | Your DIY Form 1 Silencer Kit

JK Armament 155R MST Solvent Trap Ruger American in .308 Win with a Magpul stock

From our last count, there were somewhere around 50 silencer companies operating in the United States plus countless local shops. Getting a silencer in this day and age is relatively easy and mostly painless.

For the uninitiated, if you live in a free state, buying a silencer requires the payment of a $200 transfer tax, commonly called a tax stamp as one receives a large stamp when the Form 4 is approved.

The Form 4 is an BATFE document filled out by the transferees and sent off with the $200 to the BATFE for a review process that usually takes somewhere between 9 and 12 months. This unnecessarily long waiting period detracts from many first-time silencer buyers. A reaction to such a long waiting period is JK Armament and their line of solvent traps and accessories.

DIY Form 1 modular silencer - JK Armament Solvent Trap

JK Armament is the brainchild of Jake Kunsky, a U.S. Army veteran with over 20 years of weapons and machining experience. Kunsky has worked for numerous weapons companies including NEMO Arms, Gemtech, and Maxim Defense where he has helped create some of today’s silencers and weapons.

The lessons he learned at those places helped him create his own company in 2019 in his hometown of Bruneau, Idaho. His passion for silencers led him to JK Armament and the JK155 MST (Modular Solvent Trap) kits.

JK Armament solvent trap, a DIY modular silencer kit


Solvent traps are nothing new. They were created to give consumers a chance to skip the 9-12 month wait from the ATF Form 4 process.

You see, a solvent trap can be modified into a silencer legally so long as the consumer files a BATFE Form 1.

A Form 1 is an “Application to Make and Register a Firearm” allowing the consumer to make a silencer once the Form is approved. The process can take as little as 3 weeks, especially with the BATFE E-Forms system. So now instead of several months, it is a few weeks.

JK Armament Solvent Trap DIY Form 1 Silencer Kit

JK Armament’s solvent traps are different from many others in that they are modular, allowing the consumer to choose how long the trap can be. The kits ship with the main body, a thread mount, an end cap, and eight cups (note: the cups are not baffles until they are drilled) making the kit 8.25” long, this is important information when filling out a Form 1.

JK Armament solvent trap kit components

Each cup and the end cap are solid and require modification to do any sound reduction, JK sells a drill jig to help with the process.

Another notable feature of the JK Armament solvent trap kit is that it is threaded in an almost industry standard of 1.375-24 TPI, the diameter is 1.55” as well. This thread pitch is common for SilencerCo, Dead Air Armament, Q, Griffin Armament, Area 419, Energetic Armament, and Yankee Hill Machine. This means that users who already have those types of muzzle devices can use the corresponding mounting hardware. For a new user with no specific muzzle device, JK offers a thread mount in 5/8-24 or ½-28, two other industry-standard pitches for barrels.

This is the thread mount showing the “nut” for tightening to a barrel.

This is the thread mount showing the “nut” for tightening to a barrel.

Solvent Trap Construction and Capabilities

Silencer buffs may be questioning the material choice for the solvent trap, as they are made from 7075 aluminum. Most of the silencers on the market nowadays are steel, titanium, or another denser and tougher material.

Realistically, a hobby silencer can be made from lighter-weight materials, especially one geared toward rimfire and pistol cartridges. JK says their R version solvent trap can be used up to 300WM, and we are sure it can. However, there are better material choices for a cartridge such as that.

The aluminum keeps the weight down and can withstand the most popular .223 Remington, but it is important to note that barrel length plays an important role. JK says not to use their trap on anything less than 14.5”, so the popular 16” is fine although not with full-auto fire.

We suspect the main concern will be erosion of the first few baffles (cups) from the high pressure and heat although we do not feel the need to test this theory on our trap.

Customizing the JK155 Modular Solvent Trap

Modifying the solvent trap is made easier with the sold-separately drill jig, which is caliber specific. We found it best to use a corded drill and go slowly with each cup. A bench vise will make the process significantly better as well.

solvent trap cup modification on bench vise

Our sample was bored to .35 caliber (9mm) to clear common .30 caliber projectiles and be compatible with pistol caliber carbines. We opted for a direct thread mount in 5/8-24, as the intended host is an 18” Ruger American in .308 Winchester.

JK Armament 155R MST Ruger American in .308 Win with a Magpul stock.

Silencer Performance

Compared to similarly-sized, factory-produced silencers, the JK holds up in sound reduction to our seasoned ears. The aluminum does heat up quickly but conversely, it also cools faster than steel would, making it ideal for a bolt action. The modular feature can be used to adjust the size and the amount of sound reduction wanted, we opted for maximum suppression so the length will stay at 8.25”.

The solvent trap may not be a new invention but the design and ease of use that JK Armament offers makes this a fun project for the spirited DIY’er or the newcomer to NFA items, given the reduced wait times and modularity. Few solvent traps offer this level of customization or compatibility, making it a very versatile entry into the market. We look forward to seeing what else Jake and the team bring to the market.

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Alexander Crown is an avid outdoorsman and a truly mighty gardener with a BS in biology. Prior to helping someone in Iraq earn the Enemy Marksmanship Award (and subsequent early retirement from the US Army), Alexander hailed from the 3rd Batallion, 509th Parachute Infantry Regiment out of Ft. Richardson, Alaska.  There he served in a Scout/Sniper billet where he specialized in radio communications and reconnaissance. In addition to dabbling in the world of silencers and science fiction, he enjoys reloading and woodworking.
Alexander Crown, Mag Life contributor

  • Archmark

    Stupid!!! The ATF wants your address Sport. You’ve probably also got bumpstocks & those gay stabilizing arm braces too. L-O-S-E-R!!!

    • The Destroyer

      Because of your comment, they just traced your IP address (sorry, the NSA has all ready decrypted and back-traced your true IP address, so much for that expensive VPN!) and will be knocking down your door any time now… but they might decide to wait a month or two, that way you’re not expecting it. Hope you don’t have any bump stocks or “solvent traps” kicking around!

      • John L

        LOL! Oh no now the NSA knows I have a sense of humor! I guess I better not mention those old Russian MRVs I have in my attic!

    • richard

      And you probably got a man bun and live in mommies basement like a good little soy boy

    • rick_hills

      Get a life loser

  • stphlmna

    You can make your own silencer in Idaho. Idaho considers it an accessory, not a fire arm!

    • Howlingmad

      MONTANA is the “Same” ! . . .

      • http://www.thecrimsonpirate.com The Crimson Pirate

        You will still be in violation of federal law and subject to federal prosecution. There has already been a case where one of the states with such a “firearms freedom act” refused to defend a citizen charged by the feds. The case went through the courts but IIRC the supreme court denied cert. It’s been too long and I can’t remember the details, but the citizen did not win.

  • Brian

    It never ceases to amaze me how gun owners get on the internet and talk down to each other. There are too many people whose bodies have grown up, but their minds haven’t.

    • Closet Warrior

      Here here sir, we have lost our civility.

      • Brian

        Not only have lots of people lost their civility, but they have lost their common decency as well as their common sense. I guess it’s because of the internet, people know they don’t have to look at each other face to face. Still, people should be more respectful towards others.

        • Closet Warrior

          Yep, Einstein said he feared the day technology surpassed humanity and human interaction spawning a generation of idiots…well here we are.

          • Brian

            Here we are, big time. I’ve got family members and former friends who have screwed me over. There are too many alcoholics in my family.

        • richard

          All decently is out the window this year but trust me I’d rather knuckle up face to face with a fat mouth punk like archmark

    • John Roberts

      A lot of it is lack of maturity, IMHO. It is at epidemic proportion, IMHO. Far too many people have plateaued at a junior high level of maturity, even grown men and women up through senior citizenry. Truly sad. I believe it started with my generation, the baby boomers. For a large part, us boomers have lead pampered lives, unlike the great generation that spawned us who went through the great depression and WW II. Unfortunately, it has resulted in many of us growing up as spoiled brats, and worse yet, raising even more spoiled brats. My 2 cents.

  • Jay Matt

    As usual, $75 worth of parts for $500

    • Spraghnum

      I agree, but that’s the nature of the business. You have to charge enough to make it worth the trouble to produce them. Still, you can make a Form 1 can out of better materials for a LOT less money.

  • Closet Warrior

    Am I the only one who’s gonna blast the writer for calling this devise or any other a “SILENCER”? Firstly, they don’t exist, they are called suppressors. Secondly, gun grabbers read Silecer and freak out…irresponsible. Lastly, a gun blog w/no clue to terms they shouldn’t use will eventually be used against them…silencer please. I feel articles like these don’t help the hearing act one bit.

    • http://www.thecrimsonpirate.com The Crimson Pirate

      The law says silencer

      • Closet Warrior

        Because they’re always right.

    • RangerSniperPete

      when Maxim patented the first one… it was called… wait for it… a “silencer”. it’s not that big of a deal. put your bullets in the clip and shoot on! LMAO!

      not to mention the NFA calls it a ‘silencer’ too. so there is that.

      • Closet Warrior

        No shit Sherlock, just saying suppressor is superior to silencer when speaking openly on a gun site where ignorant people see silencer and automatically think “It’s completely silent so people can go on quiet rampages w/out fear of being heard/caught”. I guess nobody else cares about the hearing act. Maybe if we keep on calling them something they’re not, it’ll change the hearts and minds of the people that hate us gun advocates…Whatever.

  • Bill J Skup

    I have one question at this time; I purchased a authentic Suppressor for a 22 SW thru all the legal channels.
    I was wondering , Do I have to purchase another certificate In order to obtain a Suppressor for a different weapon of another calibration??

    • http://www.thecrimsonpirate.com The Crimson Pirate

      Yes. You will fill out a form 1 or form 4 and pay another tax stamp for each individual suppressor.

  • Archmark

    “Stabilizing Arm Braces” are headed in the same direction as their illegitimate cousins, Bumpstocks. They’ll be deemed illegal by ATF fiat and the owner’s will be subject to prosecution if the stocks are not surrendered or rendered inoperable, all without compensation of course.

    You can thank the firearms press, especially Firearms News, for their continual depiction of braces being shouldered, which they KNOW is a no-no but stupidly believe that the ATF would never drop the hammer on the ownership and use of the braces. Sorri Chari, these idiots never learn not to shake the red rag in the face of the bull. They lose everytime, sooner or later…

    • richard

      Maybe so but I own a couple short barrel pieces with arm braces and they are anything but gay but for you to insult me and other people online is some stupid shit especially when we would defend your home and family as a good neighbor

  • stphlmna

    The value in this article as I understand it is helping Idaho citizens become aware that they can purchase this “accessory” from Idaho, made in Idaho. It is not subject to US laws regarding interstate commerce. It can then be used by Idahoans in Idaho legally and is not required to be registered with the US government. However be aware the US may not like you for that! See Crimson Trace’s comment below!