The Real Science of Airgun Suppressor Selection

[cavedweller]

So I Guess the huben K1 and the new Taipan Slash could also be good test subjects no?

Anyway, I have a ryu in my GK1 .22 and it does a good job at medium power levels. And is looks and feels great. One of the 3 donnyfl moderators I have.

The ryu in .177/.22 is a favorite of mine <20 fpe

 

[Apollo]

Talking about real science, a modular silencer with chambers of varying lengths, which can be assembled based on your airgun

Using AI to get the gun quiet.

I bought an Anschütz 9015 last year which really shoots outstanding, but it's loud, very loud. Printing a 1/2" UNF Adapter to fit in the shroud was the easy part. Tried 4 different moderators on the gun, but I wasn't happy with them. So I thought about going a different route. Took my laptop and...

www.airgunnation.com

 

[RScott]

I fully support your plan to provide a selection guide.
Also would like your perspectives on how important it is to tailor the moderator to the caliber of the pellet, e.g., can a moderator designed for .25 caliber be nearly as effective as a smaller diameter moderator for .177 pellets?
And why not offer a moderator that extends back along the shroud as well as beyond the muzzle.

Regarding prioritization of your criteria... to me, I look for maximum quieting without disrupting group size. I don't mind POI drop as long as group sizes don't widen. And all else equal, I prefer a lower longer tone versus a higher frequency noise with any sort of crack.

As far as testing, I did a lot of comparisons of moderators on my Daystate Pulsar. But I also looked at sound measuring devices. I found that examining the time/intensity plot from a decibel recorder (like a Microtrack) gave guidance more in line with my ear than a simple sound meter that shows the max decibels (e.g., BAFX). The Pulasr with no moderator was fairly quiet. With a Falx it was whisper quiet at my shooter's ear. The decibel recorder showed a significant difference with vs without the moderator. But the simple max decibel meter only showed 1 dB quieter with the moderator; perhaps it was more sensitive to the action noise.

 

[RScott]

The absolute best sound suppression you can achieve comes from an airgun that has both a shroud and a moderator, provided it has been tuned to use air properly. IMO. I'm not a big fan of BIG cans hanging from my barrel and they do cause a POI drop. I prefer the Svelte sleek nature of the Weihrauchs and Huggetts and Zero DB's. Of course reducing the diameter of a moderator means you need to maintain moderator air volume by adding more length; to me this is why a shroud really works well as the length can be kept minimal.
in the picture take notice of the silicone washer placed between the shroud and the Zero DB moderator; i'll let your tech team figure out WHY this is a good thing. I highly Recommend Donny FL offer special made washers / spacers to go between the moderator adapter and or shroud and the moderator.

What do the washers/ spacers do? Deaden sound further? Affect POI drop or grouping size?

 

[cavedweller]

What do the washers/ spacers do? Deaden sound further? Affect POI drop or grouping size?

At the end of a barrel, in-between an attached moderator, we have a hard interface between two (separate) surfaces coming together and attaching via threading forcing a mating between two flat surfaces. This juncture point creates an opportunity to mitigate some vibrational transmission or whip (some call harmonics). The use of Silicone washers, felt washers, leather washers etc... all can help to slow down, dampen or absorb some of this transmission.
In my "very unscientific tests" from my bench on no wind days, the use of a soft spacer like silicone, reduced my group sizes ever so slightly. Hard washers not so much, no washers not at all.
Another interesting trick to catch or dampen vibrational whip along a barrel is the use of thick, yet snug, O-rings placed at 1/2 the distance from the barrel to the breech, then 1/2 the distance from the middle of the barrel to the muzzle. Perhaps a silly trick but it is something we learned how to do when we were making linear / directional shape charges with high explosives. Most shooter (except indoors on a bench) will not see the difference.
Tennis players may be aware of a similar trick used on their high end rackets which helps to minimize injuries from tennis elbow.

 

[cavedweller]

I fully support your plan to provide a selection guide.
Also would like your perspectives on how important it is to tailor the moderator to the caliber of the pellet, e.g., can a moderator designed for .25 caliber be nearly as effective as a smaller diameter moderator for .177 pellets?
And why not offer a moderator that extends back along the shroud as well as beyond the muzzle.

Regarding prioritization of your criteria... to me, I look for maximum quieting without disrupting group size. I don't mind POI drop as long as group sizes don't widen. And all else equal, I prefer a lower longer tone versus a higher frequency noise with any sort of crack.

As far as testing, I did a lot of comparisons of moderators on my Daystate Pulsar. But I also looked at sound measuring devices. I found that examining the time/intensity plot from a decibel recorder (like a Microtrack) gave guidance more in line with my ear than a simple sound meter that shows the max decibels (e.g., BAFX). The Pulasr with no moderator was fairly quiet. With a Falx it was whisper quiet at my shooter's ear. The decibel recorder showed a significant difference with vs without the moderator. But the simple max decibel meter only showed 1 dB quieter with the moderator; perhaps it was more sensitive to the action noise.
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"And why not offer a moderator that extends back along the shroud as well as beyond the muzzle"
Some manufacturers do (RAW) for example has their big ol Donkey D..ks. Alan Zasadny makes some amazing shroud type moderators. Daystate and Brockock shrouds def make a difference esp when combined with a moderator. I am interested as to why no one installs thousands of pin holes within a shrouded system to further dissipate air volume existing the muzzle end. dunno?

 

[markhooper]

Hey there airheads!

The other day we sent out an email talking about all the years of experience we’ve had working with airgunners around the world—chasing down the best sound suppression possible in the airgun game. We got some great responses back, and thought, why not bring the conversation here to Airgun Nation and keep it going?

One of the big topics that came up was how air volume and internal design, whether it’s a monocore or traditional baffle stack, actually affect the shot report. Sure, there are computer models that can predict airflow and potential decibel reduction, but the reality is airguns behave very differently than firearms. They have their own quirks in how large volumes of air get expelled and how we tame that sound. Even though DonnyFL and airgun suppressors in general have been around for a while now, the science of airgun silence is still very much evolving.

When Donny first started this company, it was a lot of good old-fashioned trial and error. Just the other day, Yolanda was reminiscing about those early days, how she and Donny would stand out in the field doing A/B tests, swapping moderators back and forth, and listening closely to the differences in tone and volume. No meters. No fancy charts. Just honest, real-world feedback about what our ears told us worked best.

Over time, we’ve added sound meters and other R&D tools to the process, but we’ve learned something important: feedback from real shooters still matters more than any number on a screen. A meter might tell you it’s “quieter,” but your ears can reveal something completely different, especially downrange.

So how do you choose the right suppressor? It’s not as simple as picking the “quietest” one on the list. Caliber and power tuning matter, a hot-rodded .22 PCP can be just as loud, or louder, than a .22LR rimfire. Barrel system design plays a role too. Shorter barrels often have a sharper, louder report, while longer barrels can be sensitive to weight on the muzzle and may not play nicely with a heavy suppressor.

Then there’s how you actually use your rifle. In competition, suppression might not be the top priority, you might be more focused on how a suppressor can influence barrel harmonics. On the other hand, if you’re pesting in your backyard or working in a sound-sensitive area, maximum suppression becomes a must-have.

The quick and dirty rule is that more internal volume usually means better airgun suppression. But that’s oversimplifying it. Tone matters just as much, and in some cases, going with a really long moderator may hurt the balance or handling of your rifle.
We’re working on a comprehensive air rifle suppressor selection guide to help make those decisions easier. In the meantime, we want to hear from you. The best part about the DonnyFL community has always been the feedback we get from real shooters. We started out as a grassroots company right here in the online forums, and that community-first approach will always be part of who we are.

So, how do you judge airgun suppressor effectiveness? Is it tone, volume, group size, or a mix of everything? Got a favorite testing method you trust? Let’s make this thread a go-to resource for anyone looking to get the most out of their airgun sound suppression. Also, check out our full lineup of airgun moderators and air rifle suppressors!

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I have a Donny FL shogun that I got for my 22 caliber airforce Condor.. it's internal bore where the pellet comes out is 0.357
now if think that if it was a smaller diameter it would silence better.. like 0.25 instead of 0.357..
Mark