Christine's CoS silencer rifle is a unique weapon in the Fallout: New Vegas add-on Old World Blues. The weapon is highly accurate, being able to put accurate fire from over a mile away. The weapon features new projectiles, new textures, new meshes, and a rather beautiful explosion. This mod adds a very large sniper rifle, known as the Hyena Infra-Dead to Fallout: New Vegas.
Fallout 3 has a sniper rifle hidden in a secret rock right at the start of the game. The gun deals extremely high damage but fires very slowly.