CMMG Mk3 Ejection Port Cover Kit 308 Win AR-10 Black 38BA538

The CMMG 38BA538 Mk3 Ejection Port Cover Kit provides essential dust protection for .308 Winchester AR-10 platform rifles. This precision-engineered component seals the ejection port when the bolt is closed, preventing debris contamination that can cause malfunctions during critical moments.

What Makes This Different

CMMG's Mk3 ejection port cover features enhanced spring tension and precise tolerances specifically engineered for the larger AR-10/.308 receiver dimensions. Unlike generic covers that may bind or fail to seal properly, this kit includes all necessary hardware with exact specifications for reliable operation. The black anodized finish matches standard military specifications and resists corrosion in harsh environments.

Key Features

• Precision-machined aluminum construction with Type III hard anodizing
• Spring-loaded mechanism automatically opens during firing cycle
• Complete installation kit includes cover, spring, and pivot pin
• Compatible with DPMS-pattern AR-10 and .308 Winchester receivers
• Matte black finish matches standard military components
• Heat-treated steel spring rated for 10,000+ cycles
• Drop-in installation requires no gunsmithing or modifications

Field testing demonstrates consistent operation across temperature ranges from -20°F to 140°F without binding or failure to close. The cover maintains positive sealing during transport, storage, and tactical movements while opening reliably under rapid-fire conditions. Law enforcement agencies report significant reduction in cleaning frequency and malfunction rates when using properly fitted ejection port covers.

Technical Specs

• Material: 6061-T6 aluminum with Type III anodizing
• Finish: Matte black, military specification
• Compatibility: DPMS-pattern AR-10, .308 Winchester platforms
• Spring: Heat-treated steel, 10,000+ cycle rating
• Installation: Drop-in, no gunsmithing required
• Weight: 0.8 ounces complete assembly
• Country of Origin: United States
• Manufacturer: CMMG Inc.

CMMG's reputation for precision manufacturing ensures this ejection port cover delivers reliable protection without compromising weapon function. Professional armorers specify CMMG components for duty rifles where failure is not an option.