Irregular Design Group Hesychia 556UK-HUB Suppressor

5.56 NATO Dedicated · HUB 1.375-24 TPI · Raw Inconel 718 · Low Backpressure · Full-Auto Rated · 11 oz · 4.18" · No Coating · NFA ⚠ STAFF NOTE: UPC not confirmed for Raw Inconel 718 variant — verify before publishing. The Irregular Design Group (IDG) Hesychia 556UK-HUB is the HUB-mount version of the Hesychia 556UK—a dedicated 5.56 ultra-compact monolithic Inconel 718 suppressor on a 1.375-24 TPI HUB interface. Raw Inconel 718 finish—no coating applied. Laser Powder Bed Fusion (LPBF) construction with radial diamond initial chamber, early annular intakes, captured helix paths, shielded ports, and complex exterior texture in a sealed monolithic unit with critical interfaces machined afterward. 11 oz. 4.18" OAL. 1.75" diameter. 2.8" between blast baffle and front face. 1.34" chamber depth. 136 dB at ear, 140 dB at muzzle (MD dependent). Full-auto rated for 10.3" barrels and above. No host tuning required. Note on HUB packaging tradeoffs: The HUB threaded region consumes internal volume that in the native 556UK is used for gas pockets and disruption geometry. The 556UK-HUB maintains the same gas management philosophy but differs in internal volume and efficiency from the native Hesion Bow version. For maximum performance margin in this family, the Hesychia SIXK is the better option.

HUB 1.375-24 TPI Interface

HUB 1.375-24 TPI mount for cross-compatibility with HUB-threaded muzzle devices and adapters. Threadlocker for the HUB adapter to the suppressor is highly encouraged. Always use an alignment rod before first firing. IDG is not liable for improper use of third-party mounting systems resulting in damage.

Low Backpressure Gas Management

Gas enters a radial diamond structure in the initial chamber, gets disrupted and cooled, then routes into annular pathways before reaching the first blast baffle. Immediate pressure distribution across the suppressor keeps host cycling behavior closer to the unsuppressed baseline. No adjustable gas blocks, heavier buffers, or spring changes required.

Flash Control

Deep recessed exit aperture with six exit ports pulls gas from the central core where mixing is highest. Isolated annular pockets at the nose vary flow rate and encourage gas to exit at an angle away from the bore path—reduces crack associated with K-sized 5.56 suppressors.

Monolithic Inconel 718 — LPBF Construction

Inconel 718 provides dimensional stability, erosion resistance, and thermal cycling durability under hard 5.56 use. LPBF enables early annular intakes, helix paths, shielded ports, and complex interior geometry in a single sealed unit. No removable baffle stack, no user-serviceable internals.

4.18" Ultra-Compact / Full-Auto Rated

4.18" OAL at 11 oz. 1.75" diameter. 1.34" chamber depth. Full-auto rated for 10.3" barrels and above. Minimum recommended barrel length is 10.3"—shorter barrels increase blast baffle erosion and raise projectile stability risk.

Installation Notes

Install to muzzle device manufacturer's specification. Threadlocker on HUB adapter to suppressor highly encouraged. Always use alignment rod before first firing. IDG is not liable for improper use of third-party mounting systems resulting in damage.

Raw Inconel 718 — No Coating

Raw Inconel 718 surface finish with no additional coating applied. The natural Inconel 718 surface is corrosion resistant and thermally stable without requiring an exterior coating.

NFA Item

NFA-regulated item. Requires completion of NFA tax stamp process and transfer through licensed Class III FFL dealer. The IDG Hesychia 556UK-HUB delivers ultra-compact dedicated 5.56 HUB suppressor performance—uncoated monolithic Inconel 718 at 4.18" and 11 oz with low backpressure gas management.

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Specifications:

• Manufacturer: Irregular Design Group (IDG)
• Model: Hesychia 556UK-HUB
• ⚠ UPC: Confirm Raw Inconel variant UPC before publishing
• Caliber: 5.56 NATO (Dedicated)
• Material: Inconel 718
• Manufacturing: Laser Powder Bed Fusion (LPBF)
• Construction: Monolithic (Sealed)
• Mount: HUB 1.375-24 TPI
• Gas Profile: Low Backpressure
• Overall Length: 4.18 inches
• Diameter: 1.75 inches
• Chamber Depth: 1.34 inches
• Baffle-to-Front Distance: 2.8 inches
• Weight: 11 oz
• dB at Ear: 136 dB (MD Dependent)
• dB at Muzzle: 140 dB (MD Dependent)
• Test Platform: DD MK18 10.3"
• Full-Auto Rated: Yes (10.3" barrel minimum)
• Minimum Barrel Length: 10.3 inches
• Host Tuning Required: No
• Finish: Raw Inconel 718 (No Coating)