Red Dot Sight
The Red Dot Sight is an attachment featured in Call of Duty 4: Modern Warfare, Call of Duty: Modern Warfare 2, Call of Duty: Black Ops and the upcoming Call of Duty: Modern Warfare 3. It is a small sight, either round or rectangular, which featured a red led projecting a dot onto a curved mirror, allowing for precision aiming.
 Modern Warfare
Replaces the iron sight with a precision reflex sight. Available on all guns except sniper rifles and pistols. It is unlocked for a weapon after you obtain 25 kills with that particular weapon. The Red Dot Sight helps players gain accuracy from a distance and for Close Combat. Although providing excellent accuracy, for longer ranges the ACOG scope is often preferred over the red dot sight.
There isn't all that much, but it is helpful in getting a headshot, just put the red mark on your opponents head and shoot.
 Modern Warfare 2
Compared to it's rival, the Holographic Sight, the red dot sight has a much smaller footprint and obscures the view less, and a much smaller dot which is preferred by some players.
However, it zooms the view in less, and the dot is thrown off course when turning around whilst aiming down the sight, unlike the Holographic Sight which remains true.
 Black Ops
In Black Ops, the sight acts much like it did in previous games. However, for the first time, the reticule, reticule colour and glass colour can be customised. The can be advantagous but also distracting - large reticules can obscure the view, and bad choices of colour can be hard to distinguish from the landscape; however, a small reticule of a colour which contrasts with the map can be very effective as an aiming aid.
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