Grid Defense 18" 6mm ARC Upper Receiver - Black

• Hard Coat Black Anodized
• Chambered in 6mm ARC
• 14" Free Float M-Lok Rail
• 18" 4150 Heavy Profile Barrel - Black Nitride
• 1:8 Twist Rate
• .750 Mid Length Gas System
• 5/8x24 Thread Pitch
• A2 Flash Hider
• Mil-Spec 7075-T6 Upper Receiver