Futuristic Sniper Rifle Following Color Scheme

Design a futuristic sniper rifle with the following features:

1. Color Scheme: Use a matte gray and dark green finish instead of light brown.
2. Stock Design: Opt for a more angular, geometric stock shape that gives a more aggressive look.
3. Barrel: Extend the barrel and incorporate cooling vents along the top side.
4. Scope: Replace the linear scope with a digital holographic sight that has a wider profile.
5. Grip: Modify the grip to be more ergonomic with rubberized textures for better handling.
6. Compartment: Add a small integrated compartment for extra ammunition storage on the side.
7. Environment: Set the rifle against a textured concrete background instead of a plain one to give it a more tactical feel.

Focus on a sleek, modern aesthetic while ensuring it feels functional and robust.