It appears only once in Call of Duty: Modern Warfare 3, attached to the Starstreak as an integrated attachment. It is used to guide its missiles to its targets when playing Vertigo on solo. In co-op, however, one player uses the Starstreak while another guides the missiles with a Laser Sight on their gun.
The Laser Sight is available to all weapon classes in Call of Duty: Black Ops II, excluding launchers and special weapons.
Laser Sight increases the hip fire accuracy of a weapon, essentially replacing the Steady Aim perk from previous Call of Duty games.
When attached to a weapon, it emits a beam of light pointing where the weapon is facing, tightening the hip fire crosshairs and thus increasing the weapons hip fire accuracy by reducing the bullet spread. Contrary to widespread belief, the rounds do not land exactly where the laser points. The laser, which emits from the gun, can only be seen by the player using it and not the other people, and the beam of light becomes completely invisible when the player aims down the sights of the weapon.
It affects each weapon class differently. Submachine Guns benefit the least from this attachment, whereas the Shotguns benefit the most, with Sniper Rifles, Light Machine Guns, and Pistols in between. It grants roughly a 50-70% accuracy increase over all weapon classes. There is a potential disadvantage to this attachment; while it will aid the player if they are accurate, a weapon with no Laser Sight will compliment players who have inferior aim by giving them a bigger hipfire area, thus a higher chance to hit enemies when not looking directly at them.
A Laser Sight mounted on a MP7 (Note the rail cover on the left side of the gun has been taken off even though it isn't in use).
Turning on the Laser Sight on the Chicom CQB. It should be noted that turning on the Laser Sights replaces the cocking animation at the start of a multiplayer match.
The Laser Sight returns in Call of Duty: Ghosts, and it is only integral to the ARX-160, the Chain SAW, and the MAAWS. The MAAWS is fitted with a laser sight in all game modes, whereas the ARX-160 and the Chain SAW are only equipped with one in multiplayer. This attachment has the same effect on the ARX-160 and Chain SAW as from Black Ops II: it reduces the radius of the hipfire circle, thus making hipfire accuracy a lot better. The one on the MAAWS however, is used to laze targets for the rockets. It is possible to pair this attachment with Steady Aim, leading to the best hipfire accuracy.
The laser sight on the ARX-160. Note the emitter behind the front sight.
It decreases the radius of the hip-fire cone by 15%. The Laser Sight is significantly weaker than past iterations of the attachment.
It is best paired with weapons that are Akimbo by default (XMG and SAC3), as it increases accuracy overall instead of just accuracy without aiming. Additionally, the Laser Sight is once again present on the MAAWS by default to guide the rockets.
The Laser Sight is available for all weapons except the Combat Knife, Sniper Rifles and Launchers. The Laser Sight acts similarly to its predecessors, by decreasing bullet spread upon firing from the hip. In Infinite Warfare, this attachment can be paired with Dual Wield, makes Akimbo weapons accurater.
Usage of the laser sight is majorly beneficial when equipped on a submachine gun or assault rifle, as these weapon classes provide a viable last ditch option in ambushes or surprise attacks laid upon the player.
If used on Sniper Rifles (except those with an ACOG scope), when the player aims down the sights, the laser beam will disappear. The Laser Sight shares this trait with the "cg_laserForceOn 1" console command from earlier games; this is because the weapon model disappears while in a scoped view (scope layer).
In the campaign, the player can seldom find a weapon with Laser Sight and Dual Band Scope despite this combination is impossible when customizing the loadout.
It should be noted that when the Laser Sight is equipped on all primary weapons, the character will turn on the Laser Sight when he picks up the weapons or a game begins.
The MP7 with Foregrip attached won't be affected by this.