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GDM® 556K Rifle Suppressor

Compact. Durable. Duty-ready.

The GDM® 556K is the compact suppressor in the GDM® 556 Series — engineered for shooters who want effective 5.56 suppression in a shorter, more maneuverable package. Built from 17-4 stainless steel and finished in DLC, the 556K is designed to withstand hard use while maintaining compatibility with industry-standard mounting systems.

Why choose the GDM® 556K?

  • Compact length for improved handling on short-barrel rifles
  • 17-4 stainless steel built for high round counts
  • Universal HUB interface (1.375×24)
  • High-temperature cerakote coating for wear and corrosion resistance
  • Force Reset Trigger (FRT) rated
  • Includes direct thread mount and wrench

Who the 556K is for:

Short-barrel rifles | Hard-use builds | Compact duty setups

$599.99

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GDM® 556K Rifle Suppressor
$599.99
  • Made In the USA
  • NFA Compliant
  • Lifetime Defect Warranty

Compatible Accessories

NFA item. Compliance required. We assist throughout the process.

GDM® 556K Rifle Suppressor

The GDM® 556K is part of the GDM® 556 Series — a suppressor platform designed specifically for 5.56 shooters who demand durability, performance, and mounting flexibility in a compact form factor.

Manufactured entirely in-house at Guardian Defense Mfg’s family- and veteran-owned facility in Dayton, Ohio, the 556K is built for shooters running short-barrel or duty-focused rifles where size, strength, and reliability matter.

At 5.75 inches long and 16.6 ounces, the 556K minimizes added length while delivering effective suppression for 5.56 platforms. Its HUB (1.375×24) interface ensures compatibility with a wide range of industry-standard mounting systems, allowing users to configure their setup without proprietary limitations.

Independent third-party testing validates the performance of the GDM® 556 Series, providing objective data and real-world confidence.

Engineered for Durability & Performance

The GDM® 556K is constructed from 17-4 stainless steel, offering excellent strength and heat resistance for high round counts and demanding firing schedules. A high-temperature Cerakote coating enhances surface hardness and corrosion resistance, ensuring long-term reliability in harsh environments.

The GDM® 556 Series is available in multiple configurations to support different mission profiles, with the 556K optimized for shooters prioritizing compactness and durability.

Universal HUB Mounting

The GDM® 556K features a 1.375×24 HUB mounting interface, providing compatibility with a wide range of popular mounting systems. This universal standard allows shooters to integrate the suppressor into existing setups without being locked into proprietary mounts.

  • Removable using the included wrench
  • Also includes 1/2 x 28 direct thread mount (additional size available for purchase)

Manufactured In-House

Every GDM® suppressor is:

  • Designed
  • Machined
  • Welded
  • Assembled
  • Packaged

In-house in Dayton, Ohio.

All GDM® suppressors are backed by a lifetime defect warranty, ensuring long-term confidence in your investment.

Additional information

Model Name

GDM® 556K
Item Length

5.75 inches
Item Weight

16.6 oz
Item Diameter

1.612 inches
Material

17-4 Stainless Steel
Finish

DLC
Mount Interface

1.375 x 24 HUB
Caliber Rating

5.56 NATO / .223 Wylde
Included Components

1/2 x 28 Direct Thread, Suppressor, Wrench
Shipping Restrictions

Suppressors can only be shipped to an authorized FFL/SOT registered dealer. We cannot ship to the following states: CA, DC, DE, HI, IL, MA, NJ, NY, or RI.

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Caliber Compatibility & Use Cases

Wondering if this suppressor supports your caliber or barrel length?

Use our caliber compatibility guide to confirm supported calibers, pressure considerations, and platform recommendations before shooting.

View Caliber Compatibility Guide

Compare the GDM® 556 Series

Choose the 5.56 suppressor that best matches your build, priorities, and shooting style.

FeatureGDM® 556KGDM® 556GDM® 556Ti
Length5.75"6.5"6.5"
Weight16.6 oz18.5 oz11.5 oz
Material17-4 Stainless Steel17-4 Stainless Steel & 718 InconelGrade 5 Titanium
FinishDLCDLCDLC
Durability FocusMaximumMaximumLightweight Performance
Mount InterfaceHUB (1.375×24)HUB (1.375×24)HUB (1.375×24)
Caliber Rating5.56 NATO / .223 Wylde5.56 NATO / .223 Wylde5.56 NATO / .223 Wylde
Supported PlatformsAR-15 • 5.56 carbines • SBRs • bolt-action 5.56 platformsAR-15 • 5.56 carbines • SBRs • bolt-action 5.56 platformsAR-15 • 5.56 carbines • SBRs • bolt-action 5.56 platforms
Ideal UseSBRs / Hard useDuty / General purposeCompetition / Lightweight builds
Balance PriorityCompactnessSuppression & durabilityWeight reduction
1/2 x 28 Direct Thread✓✓✓
Made In-House (USA)✓✓✓
Lifetime Defect Warranty✓✓✓

Which GDM® 5.56 Cal Suppressor Is Right for You?

Choose based on size, balance, and suppression priority.

GDM® 556K

Choose this if you want:

  • The shortest overall length
  • A suppressor optimized for SBRs
  • Maximum durability in a compact form

Best for:

SBRs • Hard-use rifles • Compact builds

View 556K

GDM® 556

Choose this if you want:

  • A full-size 5.56 suppressor
  • Balanced sound suppression & durability
  • A general-purpose duty option

Best for:

Duty rifles • General-purpose ARs • All-around use

View 556

GDM® 556Ti

Choose this if you want:

  • The lightest 5.56 option
  • Improved rifle balance
  • Reduced front-end weight

Best for:

Competition rifles • Lightweight builds • Balance-sensitive setups

View 556Ti

All GDM® suppressors are precision-manufactured in-house in the USA and backed by a lifetime defect warranty.

Need help choosing? Our team is happy to assist before or after purchase.

Suppressors are regulated items and must be transferred through an authorized Class 3 FFL / SOT dealer.

  • Suppressors cannot be shipped to a personal residence
  • Enter your selected FFL / SOT dealer’s address at checkout
  • Orders may be canceled if a residential address is entered

We do not ship suppressors to: CA, DC, DE, HI, IL, MA, NJ, NY, RI

Always verify caliber compatibility, barrel length requirements, and firing schedule limits before use. Improper use may result in damage, injury, or voided warranty.

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