A Sniper Rifle is a type of firearm featured in the Call of Duty series designed for long-range shooting. Sniper Rifles excel at long range, where the high power, accuracy, and zoom (given by the attached scope) allow players to kill enemies at ranges other weapons would be unable to do. Sniper rifles are also one of the few weapon classes that do not lose damage over range. However, Sniper Rifles do not perform well at close range, as they have very low hipfire accuracy, long ADS times and little peripheral vision (except in Call of Duty: Ghosts).
Sniper Rifles come in bolt-action and semi-automatic fire-modes. Bolt-action Sniper Rifles have high power, allowing for reliable one-shot kills. However, these Sniper Rifles have high recoil and a low rate of fire, due to cycling the bolt between each shot.
Semi-automatic Sniper Rifles are much more diverse than bolt-action. The semi-automatic Sniper Rifles can have high power and recoil, or low power and recoil, allowing for follow-up shots if the first did not kill. Semi-automatic Sniper Rifles can be fired as fast as the user can shoot (aside from Black Ops, as all semi-automatic sniper rifles have a firecap, and the AS50 in Modern Warfare 3), unlike bolt-action Sniper Rifles.
Sniping in Modern Warfare 3 has been changed drastically. Instead of the base damage being 70 for all the sniper rifles, it has been raised to 98 (with the exception of the Dragunov and the RSASS, which are still 70). The damage multipliers for all the sniper rifles are the same, providing the same effect as previous games where some rifles would result in one shot kills from the stomach up and others would only be from the neck and head. In addition, going prone with a sniper rifle in Modern Warfare 3 has a massive benefit of reducing recoil to almost negligent amounts, allowing for rapid follow-up shots on any rifle, even the Barrett .50cal.
A noticable change from past Call of Duty games are the sniper rifle's in Modern Warfare3 have their base damage set at 98 by default, whereas in previous installments it was 70. This is because the Perk Stopping Power has been removed, which was key to sniping in Modern Warfare 2. This makes sniper rifles much more likely to score a one shot kill, even with a supressor. The lower power sniper rifles ( Dragunov & RSASS ) have their base damage at 70.
In Ghosts, the sniper rifles' scopes does not fill anymore the entire screen when aiming (similarly to the Storm PSR from Call of Duty: Black Ops II); the scopes are now dual render, allowing the player to see outside the scope while aiming, although it is very blurry. Ghosts also features a new class of similar rifles: the Marksman Rifles.
In Call of Duty: Ghosts, the new scoped view is only applied in multiplayer and Extinction; in campaign it still fills the whole screen like in previous games. However, this is fixed in the next-gen versions, where it is applied in campaign as well.