The Dead Air Sierra 5 KeyMo is the KeyMo-mount version of Dead Air’s dedicated 5.56 suppressor (Dead Air part no. SIERRA5KM). Welded Cobalt 6 baffles sit inside a stainless steel tube, and the can is full-auto rated with no barrel restrictions. The body is 4.87 inches long and 10.8 ounces without an adapter, finished in black Cerakote. Dead Air also sells the Sierra 5 with the Xeno mount, and this one carries KeyMo. It makes sense for shooters who already run KeyMo muzzle devices on their carbines.

Key Specifications

• The caliber rating is 5.56 NATO and .224 Valkyrie, per Dead Air.
• The energy rating is 2200 ft-lbs, Dead Air’s published figure for the Sierra 5.
• The bore diameter is 5.56mm, matching the dedicated 5.56 design.
• Length without an adapter is 4.87 inches, compact on a carbine.
• Diameter is 1.5 inches, a tube size that keeps the rifle balanced.
• Weight without an adapter is 10.8 ounces, light for a stainless can.
• The materials are Cobalt 6 baffles and a stainless steel tube, chosen for long service life.
• The finish is black Cerakote, a durable coating that resists wear and glare.
• The mount is KeyMo, Dead Air’s quick-detach system for fast attachment to KeyMo muzzle devices.
• It is full-auto rated with no barrel restrictions, per Dead Air.

Frequently Asked Questions

Which mount does this Sierra 5 use? This version uses the KeyMo mounting system. Dead Air also sells a Xeno version of the Sierra 5.

Is the Sierra 5 full-auto rated? Yes. Dead Air lists it as full-auto rated with no barrel restrictions, and rates it for 5.56 NATO and .224 Valkyrie.

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 Dead Air Sierra 5 5.56mm KeyMo Suppressor, Black Cerakote

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 Dead Air‘s silencers and suppressed firearms lineup and our Lubbock, Texas team will handle the transfer, and it ships fast to your Class 3 dealer. If your rifles already wear KeyMo muzzle devices, this fits right in.