Sniper Rifle

The Sniper Rifle System 99D-S2 Anti-Matériel (abbreviated SRS99D-S2 AM), more commonly known as the SRS99D-S2 AM Sniper Rifle or simply the Sniper Rifle is an extremely accurate anti-personnel weapon system used by the UNSC.

Pictures
http://images2.wikia.nocookie.net/halo/images/thumb/5/5e/SRS99D-S2_AM_Sniper_Rifle.jpg/300px-SRS99D-S2_AM_Sniper_Rifle.jpg