Air
Home to the world's quietest airgun moderators, plus precision pellet caddies, self-healing targets, chassis parts, and shooting accessories, all designed and manufactured by Silent Thunder Ordnance. From the Accipiter and Sarissa lines to the Pocket Benchrest and Eyeshine Targets, this is the full catalog of STO air products built for performance and tested before they ship.
Sarissa
Sarissa
The Sarissa is our largest standard moderator, carrying a dimensional envelope of 40x255mm and a weight of approximately 260 grams. For shooters who need maximum sound attenuation and have the rifle to justify the size, this is the one.
The design uses Nikola Tesla's Gas Diode to reflex propellant air back on itself, resisting forward flow through geometry alone with no moving parts. This three-stage approach first strips air off the pellet to reduce turbulence and improve accuracy, then delays it through compound gas diode stages, and finally passes it through a high-performance damping section to absorb residual sound energy. Critically, the design adapts along its length rather than repeating a single approach end to end, applying the right technique at the right point in the air's journey through the moderator.
The anodized aluminum tube is serviceable and modular. Cores can be swapped as the technology advances, meaning a Sarissa purchased today can be upgraded rather than replaced as new revisions become available.
Key Features:
Tesla Gas Diode design: Compound diode stages reflex and delay propellant air through geometry alone, no moving parts
Adaptive staged architecture: Design transitions along its length to maximize attenuation at each point in the air's travel
Tapered bore: Improves sound attenuation while reducing the likelihood of pellet clipping
Modular serviceable construction: Anodized aluminum tube allows core replacement as technology advances
Flow factor variants: Standard, Moderate, High, and Extra High flow cores available to match your rifle's specific output
Big bore cores available: Expanded bore options accommodate larger caliber rifles
Built and tested in the USA
Select the core whose flow factor most closely matches your rifle's calculated value. Information on calculating your rifle's flow factor can be found in our Moderator Configuration & Optimization guide.
This product is intended for airgun use only. Use of this product in any manner inconsistent with its design intent is a violation of federal law. More information about the federal court ruling which clarified the legality of airgun moderators in the United States can be found here. Local restrictions may still apply. It is the responsibility of the buyer to ensure compliance with all applicable laws.
This item ships within the United States only.
Selecting the Right Variant
Matching your moderator to your rifle's flow factor is the single most important step in getting the best performance out of a Sarissa. Our Moderator Configuration & Optimization guide walks through how to calculate your flow factor and what to do with that number. The four Sarissa variants are tuned to the following reference hosts:
Standard Flow: Tuned on an FX Crown .22, 32 ft-lbs. Factory config w/ extended shroud, acoustic peak 288.0. Flow factor 460.
Moderate Flow: Tuned on an FX Crown .30, 80 ft-lbs. Factory config w/ extended shroud, acoustic peak 637.6. Flow factor 1,111.
High Flow: Tuned on an FX Dreamline .30, 87 ft-lbs. Bare muzzle, acoustic peak 3,668.4. Flow factor 6,500.
Extra High Flow: Tuned on an AEA Challenger .35, 150 ft-lbs. Bare muzzle, acoustic peak 5,255. Flow factor 16,333.
If your rifle falls significantly outside this range, get in touch before ordering.
Sound Profile Data
A note on reading these traces: peak alone doesn't tell the full story. Post-peak sound character has a substantial effect on perceived loudness, often more than the peak value itself. Each trace is provided so you can evaluate the full sound profile rather than a single number. Note that traces are not shown to the same scale.
Sarissa Standard Flow Rev.3, as tested on a shrouded FX Crown .22. Average peak 36.32.
Rev.3 represents a complete re-engineering of our damping system, combining the diode advances of previous versions into a more integrated structure while dramatically increasing closed damping material surface area and more precisely tuning open damping material flow resistivity and impedance. The result on a standard flow host is a muzzle report roughly as loud as the hammer slap on the host rifle itself.
Sarissa Moderate Flow Rev.3, as tested on a shrouded FX Crown .30. Average peak 62.86.
At moderate flow, the Sarissa's additional length over the Falx produces a performance gain that goes beyond what simple added volume would suggest. Both peak and post-peak sound are substantially reduced, quiet enough that the rifle can be mistaken for a much lower powered platform.
Sarissa Extra High Flow Rev.3, as tested on an unshrouded AEA Challenger Pro LB .35. Average peak 262.75.
At extra high flow conditions, size becomes the limiting factor for any moderator design. The Sarissa extra high flow variant performs without qualification at this power level, delivering meaningful reductions in both peak and post-peak sound from the most demanding test host in our lineup.
