The Griffin HRT-556 AM HUB 5.56 suppressor is a black, HUB-compatible 5.56 NATO can designed with an ultra-low back pressure system to help reduce gas blowback. Griffin Armament builds it from Nickel 625X and 17-4 H900 stainless steel, with a printed core and a high-performance flash hider end cap. It runs on the industry-standard 1.375×24 HUB rear interface, so it works with Griffin HUB adapters and other compatible HUB mounts. A HUB mount adapter and compatible muzzle device are not included and must be purchased separately.

Key Specifications

• The caliber rating is 5.56 NATO, the .22 caliber bore size this can is made for.
• The rear interface is HUB, 1.375×24, which accepts Griffin HUB adapters and other HUB-compatible mounts.
• Diameter is 1.5 inches, a size that clears most handguards.
• The build is Nickel 625X with 17-4 H900 stainless steel, a printed core on a stainless rear.
• Griffin rates it full-auto with no barrel length restrictions for compatible rifle calibers.

Frequently Asked Questions

Does the HRT-556 AM HUB come with a mount? No. A Griffin pouch is included, but the HUB mount adapter and a compatible muzzle device must be purchased separately.

What makes the HRT-556 AM different from a standard 5.56 can? Griffin designs it with an ultra-low back pressure baffle stack and a flash hider end cap to cut gas blowback, recoil impulse and visible flash.

Do I need ATF approval to buy this? No. As of October 9, 2026, ATF no longer requires Form 4 approval, registration or a tax stamp for suppressors. It transfers on a Form 4473 with a background check through a Class 3 (SOT) dealer. State and local laws still apply.

Buy the Griffin HRT-556 AM HUB 5.56 Suppressor, Black

As of October 9, 2026, this suppressor transfers on a Form 4473 with a background check at your Class 3 (SOT) dealer, with no Form 4 or tax stamp; state and local laws still apply. Order through Griffin Armament‘s silencers and suppressed firearms lineup and our Lubbock, Texas team will handle the transfer, and it ships fast to your Class 3 dealer.