America's Army/M24 Sniper Rifle

See also http://en.wikipedia.org/wiki/M24_SWS

A bolt-action Advanced Marksmenship Rifle. Slow rate of fire, but maintains the scope when firing, and is relatively quiet. Clicking the 'fire' button when reloading will stop it for getting off a quick shot.

{FoM}Gurkbuster

It has an internal 5-round magazine. Because it is bolt-action however, it takes quite a while to reload completely. Very accurate, unless you are standing or walking. But once you learn to fire this while standing and walking, you'll be a force to be reckoned with.