Surefire SOCOM556

5.56 suppressor

Available in 5 versions

SOCOM556 RC4

Surefire · 5.56

$1549

MSRP

Specs on the box

Differs between versions

Mounting

Mount type: Proprietary
Included mount (differs between versions): SOCOM Series Fast-AttachCounted in weight and length
Mount removable: No

Build & use

Length (differs between versions): 6.3"w/ mount
Diameter (differs between versions): 1.5"
Weight (differs between versions): 17 ozw/ mount
Material (differs between versions): Inconel
Method (differs between versions): 3D Printed
Finish: Cerakote
Rated backpressure (differs between versions): Hybrid
User serviceable: No
Full-auto rated: Yes
Made in: USA

Check price · SurefireNon-Affiliated Link

Sound

118.3

LIAeq100ms (dB)

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

Backpressure

−3.5

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

Loading…

SCOUT REPORT

Scout Report

SilencerScout Sound Test

Metered October 25, 2026

Our take

Tracking performance along barrel length you can find this suppressor to be more agnostic to barrel length, or muzzle pressure, than it's predecessors. Historically the Socom556 line of suppressors, the RC2 in particular, has played heavily into the 10.3" barrel of the MK18 and sound performance efficiency was lost as we moved to 14.5 and longer barrels. The RC4 has avoided some of that performance falloff that RC2 going from the 10.3"/10.5" to the 14.5" finding better general utility across weapon systems. That said, the 0.7 dBa (energy equivalent) gains going from 14.5" to 18" are less than spectacular indicating this suppressor is still reliant on the higher muzzle pressures to drive performance. I personally will be keeping this suppressor on my shorter carbine sized systems.

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)	120.3	120	120	118.3	117.8	117.6
Peak (dB)	151	151.1	150	149	148.3	147.5
Peak (dBA)	147.8	145.3	141	144.9	137.6	143.6
Impulse (Pa·ms)	62.7	110.3	75.9	74.2	55.2	69.2

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	120.9	120.3	+0.6
14.5" AR-155.56 Lake City M193	120.8	120	+0.8
18" AR-155.56 Lake City M193	118.7	117.8	+0.9

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

−3.5 ms

Primer strike to bolt closed: 55.0 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
SOCOM556 RC4 · thisestimated volume	1.72	2.36

Per ounce (dB/oz)

Suppressor	SE	ML
SOCOM556 RC4 · this	0.96	1.31

The RC4 is severely punished by it's weight. This is an intentionally heavy design, and the added material is used to improve suppressor durability, firing schedule, and flash reduction. Reminder, this metric includes the permanently attached QD mount. This is roughly 5oz of weight embedded into the metric that other suppressor's with a removable mount would avoid.

Per inch (dB/in)

Suppressor	SE	ML
SOCOM556 RC4 · this	2.58	3.54

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

Riflespeed Gas Block plunger #917 on setting 3. Buffer configured with H2 and sprinco white spring.

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)	120	118.3	117.1	118	-2.9	-0.3
Peak (dB)	150	149	145.7	149.4	-4.3	+0.4
Peak (dBA)	141	144.9	141.5	144.3	+0.5	-0.6
Impulse (Pa·ms)	75.9	74.2	56.1	72.6	-19.8	-1.6

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)	120	118.3	Not yet tested	Not yet tested	119.3	116.4
Peak (dB)	150	149	Not yet tested	Not yet tested	150	146.4
Peak (dBA)	141	144.9	Not yet tested	Not yet tested	141.3	141.9
Impulse (Pa·ms)	75.9	74.2	Not yet tested	Not yet tested	68.3	55.6
	No image available		No image available		No image available

Check Price

Where to Buy

SurefireNon-Affiliated Link

Reviews & Field Reports

Links above point to third-party sites. SilencerScout does not control their content and earns no affiliate commission from these review links.