A futuristic military-grade assault rifle with a modular design. It should have a matte black and gunmetal gray finish with a reinforced polymer stock. The rifle should feature a built-in holographic sight on a Picatinny rail, an extended magazine, and a suppressor attached to the barrel. Include detailed engravings or serial numbers on the receiver, a forward grip, and an adjustable stock for a realistic touch. The weapon should appear durable and suited for combat.