The SRS99D Sniper Rifle is the primary long-range rifle used by UNSC forces. It is, alongisde its Covenant counterpart the Particle Beam Rifle, the most accurate, and arguably themost powerful infantry-sized weapon in both arsenals. The rifle's only drawbacks are its cumbersome reload and its bulky, thus necessariliy scarce, ammunition under typical battlefield circumstances.

NOTE: Although fairly similar in appearance, this weapon does have a different designation than Halo 2's sniper rifle, the S2 AM. The barrel also seems shorter than that weapon's; will it perhaps be less accurate at long range?

The "live" view through the video scope, visible when wielding the weapon and not zoomed in, was always a nice touch. I'd assume Bungie will keep it unless scenes in Halo 3 are just far too complex to allow for such a minor piece of eye candy. Aside from that, even though the contrails of sniper shots are deemed "unrealistic", especially for a futuristic weapon, for reasons of gameplay balance they will almost assuredly return as well.

UPDATE: In the Public Beta, the viewscreen is a vector rendering and not a full-color video image as in Halo 2.