The Otter Creek Labs Infinity 556K suppressor in black is a 5.56 NATO can that takes the design of the full-size Infinity and packs it into a shorter, lighter body. It is built from DMLS-printed Haynes 282 superalloy, which removes the weld seams that are common failure points in conventionally built cans. The swappable end cap system lets you tune backpressure for your host instead of accepting a fixed default. At 5.5 inches it is short enough for AR-15 and SBR builds. The rear thread is the HUB 1.375×24 pattern, so you choose the mount that fits your rifle.

Key Specifications

• The caliber rating is 5.56 NATO and 6mm, the cartridges the Infinity 556K is built around.
• Length is 5.5 inches, a compact footprint that keeps short builds handy.
• Weight is 14.5 ounces without a mount, light for a superalloy rifle can.
• The body is DMLS-printed Haynes 282 nickel-cobalt superalloy, with no weld seams or joint interfaces.
• The rear thread is HUB 1.375×24, which works with Bravo and many direct-thread and QD mounts.
• The end caps are interchangeable back pressure caps, with a medium vented cap included and low and high caps sold separately.
• The finish is black, matching most AR-15 builds.
• The package includes the suppressor, a medium back pressure end cap and stickers, with no mount.
• The suppressor carries a lifetime warranty from Otter Creek Labs.

Frequently Asked Questions

How does the Infinity 556K mount? It uses a 1.375×24 rear thread, the HUB pattern, so you pair it with a compatible direct-thread or quick-detach mount. A mount is not included.

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.

Can I change the back pressure? Yes. It ships with a medium vented end cap installed, and low and high end caps are available separately.

Buy the Otter Creek Labs Infinity 556K 5.56 NATO 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. A short 5.56 can on a HUB thread leaves the mounting choice to you, and the end cap system lets you tune it to the rifle. Order through Otter Creek Labs‘s suppressors lineup and our Lubbock, Texas team will handle the transfer, and it ships fast to your Class 3 dealer.