SIEGEROC556L
6mm / 6.5mm suppressor · HUB 1.375x24 interface · specs and compatibility from the manufacturer
Notable features
- HUB Compatible
- TBAC Summit Tested
- Full-Auto Rated
length
7.45″
weight
18.06oz
MSRP
$1,049
length
7.45″
weight
18.06oz
calibers
5.56 | 6.5
material
Steel · Inconel
interface
HUB 1.375x24
MSRP
$1,049
- Overall length
- 7.45″
- Class
- 6mm / 6.5mm
- n
- 123
- Range
- 3″–9.7″
- Median
- 6.15″
- Diameter
- 1.5″
- Weight
- 18.06 oz
- Class
- 6mm / 6.5mm
- n
- 123
- Range
- 4.4 oz–23.9 oz
- Median
- 12.5 oz
- Material
- Precipitation Hardening SS & Inconel Linear Diffuser Array
- Finish / treatment
- Black Nitride
- Max caliber
- 6mm ARC
- Base interface
- HUB 1.375x24
- Full-auto rated
- Yes
- Barrel restriction
- 10" minimum
- Minimum barrel length: 10 in.
- Firing schedule
- Full-auto rated (non belt-fed). 7.5"-8.3" barrels: semi-auto and limited full-auto, up to 90 continuous rounds then cooldown (muzzle brake recommended). 10.3" barrels: semi-auto and full-auto, up to 150 continuous rounds then cooldown. 11.5"+ barrels: semi-auto and full-auto, up to 210 continuous rounds then cooldown.
- MSRP
- $1,049
Longer than most 6mm / 6.5mm suppressors
Length compared against the 123 6mm / 6.5mm suppressors in the catalog that publish one. Quartile basis; a value inside the middle half carries no note.
Heavier than most 6mm / 6.5mm suppressors
Weight compared against the 123 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
The HUB 1.375x24 is an open standard: 468 mounts and 882 muzzle devices in our catalog fit this suppressor, including SIEGE OMNIHEX 1/2x28, 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 BuilderThe Thunder Beast Silencer Summit fires every suppressor entered on the same gun, with the same equipment. ROC556L was measured in 1 test. Figures can only be compared with others from the same test, so each one links to everything else fired on that gun.
Gas-operated rifles and carbines
Measurements published by Thunder Beast Arms Corp. How to read these
Manufacturer claim
- Full-auto rated (non belt-fed). 7.5"-8.3" barrels: semi-auto and limited full-auto, up to 90 continuous rounds then cooldown (muzzle brake recommended). 10.3" barrels: semi-auto and full-auto, up to 150 continuous rounds then cooldown. 11.5"+ barrels: semi-auto and full-auto, up to 210 continuous rounds then cooldown.
- At the core of the ROC556L is Siege Suppressors' Linear Diffuser Array, a maintenance-free internal design that efficiently manages gas flow through the suppressor, supporting reliable cycling, reduced gas to the shooter, and consistent performance.
- The Siege Direct Thread Mount is torqued into the suppressor's HUB socket to 30 ft-lbs; the suppressor is then torqued onto the host firearm's muzzle threads to 25 ft-lbs.
- The Direct Thread Mount incorporates the Siege HexRescue System: a standard 5/8" socket and ratchet can back the mount out from inside a handguard on short-barrel AR15 SD builds if it ever comes loose in place.
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- Manufactured using a proprietary bonding process rather than 3D printing, the ROC556L features smooth, polished internal surfaces that help resist carbon buildup and maintain consistent performance over time.
- ROC suppressors are manufactured from Inconel and heat-treated 17-4 stainless steel, providing exceptional strength, heat resistance, and erosion resistance under demanding firing conditions.
- When used with quality factory-loaded SAAMI or C.I.P spec ammunition, the ROC-556's free-flowing internal design is self-cleaning; the main areas needing attention are the muzzle-device and suppressor threads and alignment tapers.
- With increased internal volume compared to shorter configurations, the ROC556L delivers enhanced suppression and a smoother shooting experience, making it well suited for duty rifles, training use, and extended firing schedules. It also performs exceptionally well on 6mm ARC platforms.
- DT bundle ships with: ROC556L suppressor, 2 Siege spanner wrenches, a Siege OMNIHEX Direct Thread Mount, and a 5.56mm vented removable endcap.
- QD bundle ships with: ROC556L suppressor, 2 Siege spanner wrenches, a Siege STRONGHOLD HUB Adapter, the buyer's chosen Plan-B-compatible muzzle device, and a 5.56mm closed removable endcap.
- Minimum barrel length: 10 in.
- Host firearm muzzle threads must be 1/2x28. Siege recommends a host with threads that meet or exceed SAAMI spec .500-28-UNEF-2A <=.225 bore diameter.
