Instructions
Play online matches via Xbox Live in order to level up and unlock perks and advanced weapons.
Select the gun to which you would like to add a laser sight. Laser sights are available for all handguns, shotguns, machine pistols, light and sub-machine guns and assault rifles.
Stick with your gun of choice until you earn enough kills to unlock the red dot sight. Assault rifles, for instance, require 25 kills, while machine pistols require 10. The game will alert you when you have unlocked the sight.
Equip the red dot sight in between games in the class customization menu.
Earn kills by aiming down the red dot sight to unlock the holographic sight. Once again, the specific number of kills depends on the class of weapon, and the game will let you know when the holographic sight is available.