Airgun pistols and compact carbines are some of the most fun guns in the safe, but they are also the guns where a big moderator ruins the whole point of owning them, because nobody wants a pistol with a beer can hanging off the front. That is exactly the job the DonnyFL Tanto was built for, and it is one of the best selling moderators we have for a reason. In this Field Notes post I want to walk through why the Tanto works so well on short guns, which endcap and caliber to pick, and the adapters that get it onto the Huben GK1, the Benjamin Marauder Pistol and a few other favorites.
The DonnyFL Tanto, the short version of the KOI at 1.22 x 5 inches, built for pistols and compact PCPs.
Quick Summary
- The moderator: DonnyFL Tanto, 1.22 x 5 inches (5.37 inches with the cone endcap), 3.5 to 4.1 oz depending on endcap, mono-core, pre-wrapped in felt.
- Calibers: .177/.22, .22/.25 and .25/.30.
- Endcaps: 1/2 x 20 Bolt, FX M20x1 Bolt, 1/2 x 20 Cone, Vulcan M14x1.25 and Diana Skyhawk M12x1.25, with spare KOI/Tanto Endcaps available.
- Pistol adapters: Huben GK1, Marauder Pistol and the 1.5 inch A78 P-Rod extender, plus the slide-on Crosman 2240.
- Sizing rule: on a shrouded barrel with an adapter, go one size up, so a .22 pistol gets the .22/.25 Tanto.
What Makes the Tanto Different From the KOI
The Tanto is the shorter version of the DonnyFL KOI, so it keeps the KOI's slim 1.22 inch diameter and the rugged front cap but cuts the length down to 5 inches, or 5.37 inches with the cone endcap installed. Depending on which endcap you run, it weighs between 3.5 and 4.1 ounces, which is light enough that a pistol still points and balances like a pistol.
Do not let the size fool you, though. Inside it is the same precision CNC machined mono-core design as the bigger DonnyFL moderators, sandblasted and anodized, and it comes pre-wrapped in felt, and it performs really well even on surprisingly high-powered guns. The mono-core keeps the bore line through the moderator straight and concentric, which is a big deal on a short barrel where you have very little margin for a projectile to clip on the way out.
The Tanto keeps the signature DonnyFL grooves for grip and swaps rear endcaps to fit different threads.
Choosing the Right Tanto Endcap and Caliber
Endcap threads
The Tanto uses swappable rear endcaps, and it is available with a 1/2 x 20 Bolt, an FX M20x1 Bolt, a 1/2 x 20 Cone, a Vulcan M14x1.25 or a Diana Skyhawk M12x1.25. The 1/2 x 20 Bolt is the most common choice because most DonnyFL adapters finish in 1/2 x 20 UNF, and the published weights are 3.9 oz with the 1/2 x 20 Bolt, 4.1 oz with the 1/2 x 20 Cone and 3.5 oz with the M20x1 Bolt.
The cone endcap is worth knowing about on certain pistols, because its tapered shape lets the moderator sit closer to the shroud and leaves room for things like a fill port, which comes into play on the Marauder Pistol below. If you ever change guns, the spare KOI/Tanto Endcaps let you re-thread the same moderator instead of buying a new one.
Caliber sizing
The Tanto comes in .177/.22, .22/.25 and .25/.30 sizes. The rule of thumb we use across the DonnyFL line is simple: if you are threading directly onto a barrel, buy the same size as your airgun, but if you are going onto a shrouded barrel through an adapter, go one size up. So a .22 caliber Marauder Pistol with its factory shroud gets the .22/.25 Tanto, and that extra bore clearance is cheap insurance against a clip.
Fitting the Tanto to the Huben GK1
The Huben GK1 is one of those guns that puts a grin on your face every time you pick it up, and the Huben GK1 Pistol Adapter lets you add a 1/2 x 20 moderator or muzzle brake to it. It is 6061 T6 aluminum in black anodize with a knurled thread protector, so you can run it bare and keep the threads protected when the moderator is off.
On a pistol like the GK1 the Tanto is the natural pairing, because the whole appeal of that gun is how compact it is, and the Tanto adds suppression without making it front heavy. If you want to turn your GK1 into more of a carbine with a stock or brace, Saber Tactical makes a GK1 stock/brace adapter, and with a Tanto on the front you end up with a really handy little backyard friendly setup.
The A116 adapter gives the Huben GK1 1/2 x 20 threads for a Tanto or other DonnyFL moderator.
The Benjamin Marauder Pistol and Daystate Huntsman Regal
The A17 adapter screws into the factory shroud of both the Benjamin Marauder Pistol, which a lot of people call the P-Rod or the Woods Walker, and the Daystate Huntsman Regal. The side that goes into the shroud is 11/16 x 24 and the moderator side is 1/2 x 20. Our top recommendation on those two guns is actually the Sumo with 1/2 x 20 threads, sized a half step up to .22/.25 for a .22, but there is a catch on the P-Rod, because with a Sumo on the front you have to remove it to fill the gun.
That is where the Tanto shines. You can run a Tanto or KOI with the cone rear cap, or step up to the A78 P-Rod Extended Adapter, which extends the shroud 1.5 inches, or about 38.1mm, and pair it with a .22/.25 Tanto with the 1/2 x 20 Bolt endcap. That combination makes the pistol very quiet and you do not have to pull the moderator to fill it, which is the kind of small thing that makes you actually enjoy shooting the gun.
Shop the P-Rod Extended Adapter
More Short Guns That Love a Tanto
The Crosman 2240 has been the gateway airgun for a lot of us, and the Crosman 2240 Adapter is a slide-on adapter with a 7/16 inch inner diameter and 1/2 x 20 UNF threads, plus a knurled thread protector. A .177/.22 Tanto on a 2240 is about as fun as a backyard plinker gets.
Beyond that, any compact PCP that finishes in 1/2 x 20 through one of our adapters is a candidate, and you can browse the full list on the DonnyFL adapters collection. If you are not sure which one fits your gun, measure the barrel or shroud with a caliper and reach out before you order, because getting the adapter right is what makes the whole setup work.
Tanto Setup Checklist
Pick the endcap thread that matches your adapter, which is 1/2 x 20 Bolt for most DonnyFL adapters.
Go one caliber size up when the adapter goes onto a shroud.
Thread it on by hand until it seats squarely, then re-check zero.
Pull the mono-core every so often and inspect the felt, since it comes apart with no tools.
Frequently Asked Questions
How long is the DonnyFL Tanto?
The Tanto is 1.22 inches in diameter and 5 inches long, or 5.37 inches with the cone endcap installed. It weighs 3.5 to 4.1 oz depending on the endcap.
What calibers does the Tanto come in?
The Tanto is available in .177/.22, .22/.25 and .25/.30. Go one size up when you mount it on a shrouded barrel through an adapter.
What is the difference between the Tanto and the KOI?
The Tanto is the shorter version of the KOI. Both share the slim 1.22 inch diameter and mono-core design, but the KOI is 7 inches long for more suppression, while the Tanto is 5 inches for pistols and compact rifles.
Which adapter fits the Huben GK1?
The DonnyFL Huben GK1 Pistol Adapter A116 adds 1/2 x 20 threads for a moderator or muzzle brake and includes a knurled thread protector.
Can I fill my Marauder Pistol with a moderator installed?
With a Sumo on the A17 adapter you have to remove it to fill the P-Rod. Running a Tanto or KOI with the cone rear cap, or the A78 extended adapter with a .22/.25 Tanto, lets you fill the gun without removing the moderator.
Will the Tanto work on a high-powered gun?
It performs really well even on high-powered guns for its size, but if suppression is the priority on a high-power .25 or .30, a larger moderator like the Sumo or Shogun will be quieter.
Final Thoughts
So if you have a pistol or a compact PCP that you love because it is small and handy, the Tanto is the moderator that keeps it that way while taking the bark down to a backyard friendly level. Get the right adapter, go one size up on shrouded guns, and you will have a little setup that is an absolute blast to shoot.
