FORTITUDE 5.56 HD Silencer

A full-size 5.56 silencer built in hardened, heavy-duty Inconel — made for sustained fire, heat, and the rifles that don't get to cool between strings. Its integral reduced-backpressure endcap vents gas forward, keeping blowback off your face and your rifle running clean.

Inside, a helical baffle core and internal acoustic texturing do the patient work of bringing a NATO round down to something civil. It's HUB-compatible and ships with a 1/2×28 direct-thread mount, so it moves from host to host without ceremony — built to shrug off a schedule of abuse.

Acoustic Golfball Dimpling™

Internal dimpling deepens the tone and increases internal volume — matching what an undimpled silencer would need ~1.5″ of extra length to achieve.

Jet-Turbine Diffuser Endcap™

Releases and disperses hot gas at the muzzle for faster cooling, further reducing flash and muzzle signature.

Will It Fit My Gun?

• Caliber: .223 Rem / 5.56 NATO
• Base: 1.375×24 Hybrid Universal
• Mount: 1/2×28 with Integrated Flash Hider

How Big Is It?

• Length: 5.00 in.
• Diameter: 1.69 in.
• Weight: 11.50 oz.

What's It Made Of?

• Material: Inconel 625
• Construction: Laser Powder Bed Fusion
• Finish: Cerakote

Integrated Wrench Flats

Built into the base of the body, so the silencer indexes and comes off with a standard wrench — no proprietary tooling.

Tripass Core Technology™

Three gas paths — a central bore and two helical bypass channels — feed three expansion / mixing chambers, where counter-clockwise blades disrupt and cool gases to significantly reduce sound signature, without inducing backpressure. LEARN MORE

HUB-Compatible

Runs the industry-standard HUB interface, so it fits mounts you may already own. Ships with a 1/2×28 direct-thread mount.

HUB Mounted Brake™

Our 1/2×28 direct-thread mount, machined from 17-4 stainless steel, with an integrated brake that cuts muzzle flash at the source. Hex drive for quick install and removal.

Recommended Firing Schedule

Published in the SAAMI Z299.6 format. A rating is a schedule, not an adjective — below are the cartridges, barrel lengths and firing cadences the FORTITUDE 5.56 HD is built to run, and the round count at which it needs to cool.

CARTRIDGE MIN. BARREL MAX. CADENCE ROUNDS BEFORE COOLING

.223 Rem / 5.56 NATO 10.3 in. 60 rpm 240

.223 Rem / 5.56 NATO 10.3 in. 200 rpm 150

.223 Rem / 5.56 NATO 10.3 in. Cyclic 120

6mm ARC 10.3 in. 60 rpm 204

6mm ARC 10.3 in. 200 rpm 127

6mm ARC 10.3 in. Cyclic 102

.243 Win · 6mm Creedmoor · 6 Dasher · 6 BR · 6 GT 18 in. 30 rpm 90

What “cool” means. A temperature, not a wait time. Point an infrared thermometer at the outside of the silencer, and when it reads 150 °F or less, go again. How long that takes depends on the day.

Shooting something we didn’t list? If it’s the same bore size or smaller than a cartridge in the table and it carries less energy, you can run it at that row’s numbers. If nothing in the table covers it, you’re outside the schedule — give us a call and ask.

What if you go past it? Nothing in this table is a cliff. There’s no round count where the silencer stops being safe, and we’re not going to pretend there is. These are simply the numbers we’ll stand behind. Run well past them and break something, and that damage isn’t covered — and we work that out by looking at the silencer, not by asking you what you were doing with it.

The rest of it — the full schedule, how to cool it, what to look for — is in the owner’s manual.