Dead Air Sierra 5

5.56 suppressor

Available in 2 versions

Sierra 5 Xeno

Dead Air · 5.56

$899

MSRP

Specs on the box

Differs between versions

Mounting

Mount type: Hub
Rear thread (differs between versions): 1.125×28
Included mount (differs between versions): Xeno Mount With 1/2x28 Flash Hider
Mount removable (differs between versions): Yes

Build & use

Length: 4.87"
Diameter: 1.5"
Weight: 10.8 oz
Material (differs between versions): Stainless Steel, Cobalt 6
Method: Welded
Finish: Cerakote
Rated backpressure: High
User serviceable: No
Full-auto rated: Yes
Made in: USA - TX

Check price · Dead AirNon-Affiliated Link

Sound

119.7

LIAeq100ms (dB)

Muzzle · 14.5" AR-15 · 5.56 Lake City M193

Backpressure

−9.3

Change in cycle time (ms)

Primer strike → bolt closed, vs bare host

Flash

Not yet tested

Metric TBD

Stand-in — not yet defined

BACKPRESSURE0.0ms

FLASH--

Add to Gauge

Must share caliber · 5.56 · Must be tested

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SCOUT REPORT

Scout Report

SilencerScout Sound Test

Metered July 28, 2026

Our take

Dead Air's first entry into the 5.56 market, this traditional high backpressure can is a solid performer at the muzzle. The Sierra 5 is good at keeping noise out of the environment around the shooter, making it a great choice if you shoot indoors or around other shooters. The strong muzzle performance comes at the cost of elevated readings at the shooter's ear, above other suppressors in its class. This elevated shooter's ear reading is par for the course with a high backpressure design, however, this can be curbed with some simple tuning, and we encourage you to check out the tuning numbers below. Once your host firearm is tuned up a bit, this can begins to shine, with strong sound numbers, a slim, lightweight design, and a very high temp rating for full auto use. Plus, it ships with your choice of Xeno or KeyMo and gets a few style points for having knurling.

Read our full take

Sound sweep

5.56 Lake City M193 — AR-15 barrel-length sweep

Metric	10.5" AR-155.56 Lake City M193		14.5" AR-155.56 Lake City M193		18" AR-155.56 Lake City M193
Metric	SE	ML	SE	ML	SE	ML
LIAeq100ms (dB)	121.4	122	122.9	119.7	119.8	117.4
Peak (dB)	148.2	149.6	149.9	147.8	145	144.2
Peak (dBA)	146.8	144.5	143.3	142.7	141.4	140.2
Impulse (Pa·ms)	62	83.5	77	62.1	61.5	52.6

No image available

The AR-15 hosts used for the 5.56 barrel-length sweep

How to read this report

Our core performance metric is LIAeq100ms: the whole pressure curve, A-weighted to approximate the human ear, integrated over 100 ms. Peak and impulse are shown alongside for context. Every configuration is metered at SE (shooter's ear) and ML (muzzle, left side).

Sound metering methodology

About the Test Platform

Suppressors are tested across a full range of barrel lengths and gas systems. See our article on the test platforms for full detail behind our test configurations.

The AR-15 hosts behind the 5.56 tests

Cold-can first shot

First round pop

On the first shot, unburnt propellant mixes with the oxygen sitting inside the suppressor and burns a second time in the can. That secondary combustion often makes the round louder than the ones behind it. Once that oxygen is burnt off, follow-up shots settle into a quieter, steadier number. This is commonly called first round pop, or FRP. Because a hunter, marksman or defensive shooter may only ever fire one or two rounds, we isolate the first-round data rather than bury it in the average, and present it here. The magnitude of first round pop varies substantially across designs.

Shooter's ear · LIAeq100ms (dB)

Host	First round	Subsequent	Pop
10.5" AR-155.56 Lake City M193	121.9	121.4	+0.5
14.5" AR-155.56 Lake City M193	124.7	122.9	+1.8
18" AR-155.56 Lake City M193	120.5	119.8	+0.7

Change in cycle time

Backpressure

Cycle time runs from primer strike to bolt closed. Backpressure drives the bolt home sooner, so a bigger drop versus the bare host indicates more backpressure and more wear.

Change in Cycle Time

−9.3 ms

Primer strike to bolt closed: 49.2 ms suppressed vs 58.5 ms bare host

Performance for its size

Efficiency metrics

These metrics nest raw decibel performance in the important context of how well a suppressor performs for its size.

Quoted off 14.5" AR-15 · 5.56 Lake City M193. Each value is dB reduction ÷ the listed dimension, at shooter's ear (SE) and muzzle left (ML).

Per cubic inch (dB/in³)

Suppressor	SE	ML
Sierra 5 Xeno · thisestimated volume	1.83	2.87
Sierra 5 Keymoestimated volume	1.83	2.87

The performance per volume does a great job of highlighting this suppressor's strength at utilizing it's small overall footprint with efficiency. The small outer diameter helps this can keep it's footprint low giving this can respectable sound performance in a discreet form factor.

Per ounce (dB/oz)

Suppressor	SE	ML
Sierra 5 Xeno · this	1.24	1.93
Sierra 5 Keymo	1.24	1.93

Punished in weight by it's stainless steel and cobalt-6 full auto rated construction, but rewarded by it's short overall length. Nested in this context, the Sierra 5 performs very efficiently. But when compared against restricted fire titanium suppressors, it is beat out. Consider the necessity of full auto ratings when looking at this suppressor.

Per inch (dB/in)

Suppressor	SE	ML
Sierra 5 Xeno · this	2.74	4.29
Sierra 5 Keymo	2.74	4.29

The Sierra 5 is punished here by it's small outer diameter. While this construction style yields a low profile design and volumetric efficiency, it is beat by short suppressors with large diameters. This small diameter can reward a design with better stress resistance, but the dB/inch metric is agnostic to this.

Tuned vs untuned

Tuning overhead

This metric captures the tuning overhead of the suppressor when paired with sound-mitigating part choices. A valuable metric for understanding what overhead you, the end user, have to push the performance envelope. Both rows are the same barrel and the same load. Only the parts used change.

How we tuned

Tuned with YHM Suppressor Gas Block featuring a 0.061" restricted orifice. Lower tuned with standard power buffer spring an 4.6oz H2 buffer.

Metric	14.5" AR-155.56 Lake City M193		14.5" AR-15 Tuned5.56 Lake City M193		DifferenceTuned − untuned
Metric	SE	ML	SE	ML	SE	ML
LIAeq100ms (dB)	122.9	119.7	118.6	119.6	-4.3	-0.1
Peak (dB)	149.9	147.8	149.8	147.9	-0.1	+0.1
Peak (dBA)	143.3	142.7	145	142.8	+1.7	+0.1
Impulse (Pa·ms)	77	62.1	48.2	56.1	-28.8	-6

No image available

The 14.5" AR-15 host used for the 5.56 tuning comparison

Same host, different loads

Ammo test

Metric	14.5" AR-155.56 Lake City M193		14.5" AR-155.56 Lake City M855		14.5" AR-155.56 Black Hills OTM 77gr
Metric	SE	ML	SE	ML	SE	ML
LIAeq100ms (dB)	122.9	119.7	124.5	117.8	124.1	116.7
Peak (dB)	149.9	147.8	152	145.7	151.2	144.7
Peak (dBA)	143.3	142.7	144.7	141.7	143.7	139.3
Impulse (Pa·ms)	77	62.1	102.3	50.7	89.1	42.5
	No image available		No image available		No image available

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Where to Buy

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