The Scope increases zoom to almost 5x compared to aiming down the sights without. It also decreases hipfire accuracy and increases base damage from whatever it was (45-35 for the M1 Garand, 50-40 for bolt action rifles) to 70. Also, damage multipliers are changed. Note that the "Statistics" displayed in-game are misleading and oftentimes flat-out wrong. The following sections analyze the actual statistics of snipers to better help players choose a rifle to fit their needs.
Attaching a sniper scope to any of the bolt-action rifles greatly increases the weapon's sound when fired, causing it to be heard across the entire map. A possible reason for this is so that hiding snipers can be easier to find. Note that the M1 Garand is unaffected by this, making it the quietest sniper rifle.
It should be noted that on bolt-action rifles without a scope, stripper clips will be used to quickly reload the magazine. With a scope obstructing the bolt cover, rounds will be loaded one at a time, even on the Arisaka, despite the scope's offset mounting which would still allow stripper clips to be used.
When breath is held, all sniper rifles are perfectly accurate. However, idle amount differs from one rifle to the other. The rifles with the most idle amount are the Springfield, Mosin-Nagant, and Kar98k at 60 each. The Arisaka is unique in that its idle amount is reduced from 60 when standing to 45 when crouching, making it the most accurate "true bolt-action sniper". The PTRS-41 has an idle amount of 40. The M1 Garand has an idle amount of 40 when standing and 30 when crouched.
Though unscoped bolt-action rifles do have minor differences in the rate cartridges are cycled, their fire rates become the same when scoped. The Mosin-Nagant, Arisaka, Kar98k and Springfield can fire every 1.28 seconds (46 RPM). The PTRS-41 is the fastest rifle in the bolt-action category (although it is not technically bolt-action), having a delay of only 0.8 seconds between each shot (75 RPM). The M1 Garand is by far the fastest firing sniper rifle, able to fire every 0.135 seconds (444 RPM).
The Springfield, Kar98k, Mosin-Nagant, Arisaka, and PTRS-41 are all 1-shot kills to the chest, neck, or head. When coupled with Stopping Power the stomach is also a one shot kill. The M1 Garand is the weakest sniper rifle; it is only a one shot kill to the head, unless using Stopping Power, in which case the neck and chest are also one shot kills. Note that enemies with Juggernaut will negate the effect of Stopping Power, which hurts the effectiveness of the Springfield.
All sniper rifles are 1-shot kills to any part of the body in Hardcore, even if the enemy is equipped with Juggernaut and the player is not equipped with Stopping Power. Because of this, the M1 Garand is far superior to the other sniper rifles when playing Hardcore.
In Nacht der Untoten the attachment is used in the sniper cabinet. It is only available for the Kar98k and the Springfield (Through console commands). It costs 1500 points and is effective at low rounds but many players do not buy it as is a waste of money. This feature is not available on Call of Duty: Zombies, instead being replaced with a Flamethrower.
Although the sniper scope is the default sight on most sniper rifles, it is classified as an attachment in Singleplayer and Special Ops for the M14 EBR. At most times it is found with this attachment, where it is called "M14 EBR Scoped". The only time the scope is not attached is in the Special Ops mission Breach & Clear.
The sniper scope from Call of Duty: World at War returns in Call of Duty: Black Ops. In the mission Project Nova, the Mosin-Nagant, commonly dropped by friendlies, can be found with or without a sniper scope. This attachment is also available for the Kar98K in the Sniper Cabinet on the second floor of the revised Zombies map Nacht der Untoten, available to those who purchased the Hardened or Prestige editions of Call of Duty: Black Ops, or downloaded the Rezurrection map pack.
Same as Call of Duty: Modern Warfare 2, the M14 EBR in the campaign and Special Ops mission mode of Call of Duty: Modern Warfare 3 is the only sniper rifle on which the sniper scope is classified as an attachment. The only time the scope is not attached is in the Special Ops mission Arctic Recon.
Additionally, Grinch is sometimes seen using his MK14 assault rifle with a sniper scope. This one, however, is unavailable to the player.
In Call of Duty 4: Modern Warfare, Call of Duty: World at War and Call of Duty: Modern Warfare 2, all the sniper rifles have different scopes, but they have the same reticle. This is due to a programming code called scope_overlay_m40a3 which makes all sniper rifles' reticles identical to that of the M40A3 (or, in Call of Duty: World at War, the code scope_overlay_mp (which is same as scope_overlay_japanese), where the reticle used belongs to the Arisaka and PTRS-41.) This does not apply to the Barrett and the WA2000, since they have the same scope.
The sniper scope for the Springfield for the Wii is very different than that of the Xbox 360, PS3, and PC versions.