Irregular Design GroupHesychia SIXK-HUB
6mm / 6.5mm suppressor · HUB 1.375x24 interface · specs and compatibility from the manufacturer
Notable features
- HUB Compatible
- Low Backpressure
- Full-Auto Rated
- Sealed
length
4.83″
weight
11.6oz
MSRP
$850
length
4.83″
weight
11.6oz
calibers
5.56 | 6.5
material
Inconel
interface
HUB 1.375x24
MSRP
$850
- Overall length
- 4.83″
- Class
- 6mm / 6.5mm
- n
- 98
- Range
- 3″–9.7″
- Median
- 6.2″
- Diameter
- 1.65″
- Weight
- 11.6 oz
- Material
- Inconel 718
- Max caliber
- 6mm ARC
- Base interface
- HUB 1.375x24
- Front cap
- Fixed
- Backpressure
- Low
- Full-auto rated
- Yes
- Barrel restriction
- 10.3" minimum
- Maintenance
- Sealed (not user serviceable)
- MSRP
- $850
Shorter than most 6mm / 6.5mm suppressors
Length compared against the 98 6mm / 6.5mm suppressors in the catalog that publish one. Quartile basis; a value inside the middle half carries no note.
Prices are manufacturer's suggested retail (MSRP). What you pay may differ.
- Base interface
- HUB 1.375x24
- Front cap
- Fixed
The HUB 1.375x24 is an open standard: 415 mounts and 818 muzzle devices in our catalog fit this suppressor, including Irregular Design Group Hesion Bow HUB Adapter, AAC 51T S.T.A.M.P. Mount and AB Suppressor AB Raptor Adapter. You aren't locked into one manufacturer's parts.
Which ones fit your barrel and host?
Check in the BuilderManufacturer claim
- The SIXK-H is full auto rated, with an extreme low backpressure gas profile.
- Irregular Design Group measures the SIXK-H at 140 dB at the ear and 144 dB at the muzzle on a DD MK18 10.3 test platform, both muzzle-device dependent.
- In a HUB suppressor, a larger threaded region consumes space that cannot be used for gas pockets, disruption features, or flow-shaping geometry, so the SIXK-H trades some of the native system's packaging efficiency for cross-compatibility.
- Irregular Design Group designed the system so it does not need any tuning for any firearm host it mounts to — no adjustable gas blocks, heavier buffers, or different springs required to make the suppressor work.
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- The SIXK-H is the HUB version of the Hesychia SIXK, keeping the same core design logic in a cross-compatible 1.375-24 TPI HUB format.
- Compact length, 4.825" overall, with 3.24" between the blast baffle and the front face.
- Gas enters a radial diamond structure in the initial chamber, gets disrupted and cooled, then gets pulled into annular pathways early, before the first blast baffle has a chance to become a pressure traffic jam.
- The SIXK-H is a monolithic Inconel 718 body produced by Laser Powder Bed Fusion (LPBF), with the critical interfaces machined afterward.
- Inconel 718 is the material choice because it holds its shape, resists erosion, and survives thermal cycling. It is not the lightest option and not the cheapest option.
- The SIXK-H is a sealed monolithic unit. There are no user-serviceable internal components and no baffles to remove individually.
- To run IDG's proprietary muzzle devices with the SIXK-H, the Hesion Bow HUB Adapter provides the same device logic the Hesychia series was designed around.
- Always use an alignment rod before shooting for the first time, and threadlocker for the HUB adapter to the suppressor is highly encouraged.
- The SIXK-H is full auto rated for 10.3" barrels and above. The minimum recommended barrel length for the 5.56 and 6mm rifle suppressors in this system is 10.3", and going shorter increases blast baffle erosion and raises projectile stability risk.
- Because the SIXK-H is a HUB suppressor, the muzzle device used inside the suppressor has a drastic effect on overall performance. Muzzle brake or compensator type devices typically offer better suppressed performance, while open tine or caged flash hiders tend to have a slightly negative effect and can degrade the internal structure faster over time.