Centurion Arms MK11 Ambidextrous 7.62 Billet Lower Receiver

Centurion Arms MK11 Ambidextrous 7.62 Billet Lower Receiver

The Centurion Arms C4 7.62 Billet Lower Receiver is the ultimate foundation for your large-frame AR build. Precision CNC-machined from billet 7075-T6 aerospace-grade aluminum and finished in a rugged MIL-A-8625F, Type III, Class 2 hard anodized flat black coating, this receiver delivers unmatched strength, dimensional accuracy, and tactical aesthetics.

Designed to be compatible with Knight’s Armament SR-25 and LMT upper receivers, this lower offers serious builders the flexibility to create a battle-ready 7.62 platform. With support for ambidextrous controls and a deeply flared magwell, it’s engineered for fast reloads, smooth operation, and mission-grade reliability. Every receiver is proudly made in the USA and inspected for precision — because performance starts at the core.

7075-T6 Billet Aluminum
Aerospace-grade billet construction ensures maximum strength and long-term durability.

Hard Anodized Finish
MIL-A-8625F, Type III, Class 2 flat black coating resists corrosion, wear, and harsh environments.

Knights Armament Pattern Compatible
Designed to work with SR-25 and LMT uppers (minor fit variations may occur).

Ambidextrous Control Support
Compatible with ambi selectors and NORGON or Forward Controls mag releases.

Deep Beveled Magwell
Largest possible flared magwell for fast, reliable magazine changes.

Integrated Trigger Guard
Reinforced lower design eliminates the need for aftermarket guards.

Precision Machining
Dimensional accuracy inspection and hand-deburred edges for flawless fit and finish.

Made in the USA
All components, materials, and packaging are American-made.

Specifications

• Material: Billet 7075-T6 Aerospace Grade Aluminum
• Finish: MIL-A-8625F, Type III, Class 2 Hard Anodized (Flat Black) or Cerakoted per customer request
• Weight: 14.9 oz (with takedown pins and ambi release)
• Lower Receiver Compatibility: TDP/Mil-Spec 7.62 AR lower receiver parts
• Upper Receiver Compatibility: Knight’s SR-25 and LMT uppers (fit gaps may vary by generation)
• Selector Markings: Pictograph markings for 90° safety
• Magwell: Largest flared, deep beveled design
• Trigger Guard: Integrated into lower receiver
• Ambidextrous Support: Compatible with ambi selector and NORGON/Forward Controls mag release
• Edge Finishing: All sharp edges hand-deburred
• Inspection: Dimensional accuracy verified
• Warranty: Functional warranty coverage only; cosmetic preferences not eligible
• Not Compatible With: Daniel Defense DD5V1 upper receiver