Irregular Design GroupHesychia 556UK
5.56mm / .223 suppressor · IDG Hesion Bow interface · specs and compatibility from the manufacturer
Notable features
- Low Backpressure
- Full-Auto Rated
- Sealed
length
4.75″
weight
13oz
MSRP
$975
length
4.75″
weight
13oz
calibers
5.56
material
Inconel
interface
IDG Hesion Bow
MSRP
$975
- Overall length
- 4.75″
- Class
- 5.56mm / .223
- n
- 328
- Range
- 2.5″–9.75″
- Median
- 6.12″
- Diameter
- 1.75″
- Class
- 5.56mm / .223
- n
- 328
- Range
- 0.98″–2.2″
- Median
- 1.57″
- Weight
- 13 oz
- Material
- Inconel 718
- Max caliber
- 5.56mm NATO
- Base interface
- IDG Hesion Bow
- Front cap
- Fixed
- Backpressure
- Low
- Full-auto rated
- Yes
- Barrel restriction
- 10.3" minimum
- Maintenance
- Sealed (not user serviceable)
- MSRP
- $975
Shorter than most 5.56mm / .223 suppressors
Length compared against the 328 5.56mm / .223 suppressors in the catalog that publish one. Quartile basis; a value inside the middle half carries no note.
Wider than most 5.56mm / .223 suppressors
Diameter compared against the 328 5.56mm / .223 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
- IDG Hesion Bow
- Front cap
- Fixed
This suppressor's IDG Hesion Bow takes no separate mount. 6 muzzle devices in our catalog attach to it directly.
Which ones fit your barrel and host?
Check in the BuilderManufacturer claim
- The 556UK is full auto rated, with a low backpressure gas profile.
- Irregular Design Group measures the 556UK at 135 dB at the ear and 138 dB at the muzzle on a DD MK18 10.3 test platform.
- The 556UK was built to give a real rifle a shorter suppressor without accepting the usual penalties of an ultra-compact can as unavoidable: compact size, low gas to the shooter, strong flash control for the envelope, good tone at the ear, and durability under hard use.
- 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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- Flexure pawls are printed within the suppressor body under protective hoods to provide six bi-directional indexing arms that engage within 32 grooves around the outer edge of the muzzle device, adding only .5 oz. to the entire system.
- The primary lock is a 15-degree taper over 0.25" of length paired with a 1 1/8"-8 left-hand American Buttress Thread. Just 15 ft./lbs. of torque generates over 1,700 lbs. of sealing force, and full taper lock takes less than 2.5 rotations.
- The 556UK adds 2.6" of length to the muzzle device, in a 4.75" overall length at 1.75" diameter.
- The 556UK is a monolithic Inconel 718 body produced by Laser Powder Bed Fusion (LPBF), with the critical interfaces machined afterward.
- The 556UK is a sealed monolithic unit. There are no user-serviceable internal components and no baffles to remove individually.
- Install the muzzle device to the barrel at 30 ft./lbs. Timing is not required for the Micro Flow Enhancer, and threadlocker is not normally required under standard installation.
- The manufacturer lists the Micro Flow Enhancer as the only compatible muzzle device for the 556UK; on this can the Micro Flow Enhancer is the intended pairing rather than an optional accessory.
- The 556UK 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.