The Dead Air Sierra 5 is a dedicated 5.56 suppressor built for people who actually run their AR-15s hard. It's short, rated for full-auto fire and light enough at 10.8 ounces that your carbine still handles like a carbine. This version comes as a complete kit with Dead Air's KeyMo quick-detach mount and a 1/2x28 KeyMo flash hider, so it's ready to go on a standard AR barrel out of the box.
KeyMo is what makes the Sierra 5 easy to live with. The flash hider stays on the rifle, and the can locks onto it with a quick twist and comes off just as fast, with no wrenches and no fighting a hot direct-thread can. Put KeyMo muzzle devices on your other 5.56 rifles and one Sierra 5 can serve all of them. At 4.87" long bare and 6.27" with the mount, it adds little length to a 14.5" or 16" barrel.
Why shooters pick the Sierra 5 KM
- Dedicated 5.56 design, rated for full-auto with no barrel length restriction
- Stellite baffles and a stainless steel tube built for hard use
- Compact: 4.87" bare, 6.27" with KeyMo
- 10.8 oz bare, 15.4 oz with mount
- KeyMo quick-detach mount plus 1/2x28 flash hider included
- Easy to share between rifles with KeyMo muzzle devices
Specifications
| Manufacturer | Dead Air Silencers |
|---|---|
| Model | Sierra 5 (KeyMo) |
| Caliber | 5.56 NATO / .223 Rem |
| Use | Semi-auto and full-auto rated |
| Length | 4.87" (bare), 6.27" with KeyMo mount |
| Weight | 10.8 oz (bare), 15.4 oz with KeyMo mount |
| Diameter | 1.5" |
| Mount | KeyMo quick-detach; KeyMo adapter and 1/2x28 KeyMo flash hider included |
| Materials | Stellite baffles, stainless steel tube |
| Finish | Black Cerakote |
| Maker part # | SIERRA5KM |
| NFA item | Yes, serial-number tracked |
Questions we get about the Sierra 5
What comes in the box?
The Sierra 5 suppressor, a KeyMo adapter and a 1/2x28 KeyMo flash hider, so it's ready to mount on a standard AR-15 barrel.
Can I run it on a short barrel or full-auto?
Yes. The Sierra 5 is a dedicated 5.56 can rated for full-auto fire. Ask us about your exact barrel length and gas setup.
Can I move it between rifles?
Yes. Put a KeyMo flash hider or muzzle device on each rifle and the can clicks on and off in seconds.
Buying a suppressor at Guns 2 Ammo in Mesa, AZ
Order online or in store, then finish your transfer at our Mesa shop. Since 2026 suppressors carry a $0 tax stamp, and you can choose a registered eForm 4 or a same-day transfer on a Form 4473. Buy it from us and there's no transfer fee: fingerprints, photos and paperwork are handled in store, and trust setup is available. Both options are explained on our NFA & Class III page.
Outside Arizona? We can ship to your local SOT dealer. Not available in suppressor-restricted states. Questions? Call (602) 715-2677.
| Manufacturer | Dead Air |
| Model | Sierra 5 |
| Caliber | 5.56 NATO / 223 Rem |
| Type | Silencer |
| Size/Length | 6.27" |
| Item Weight | 15.4 oz |
| Diameter | 1.5" |
| Mount Type | KeyMo (1/2x28 flash hider included) |