The expanding crosshair is a reflection of real life which has become a game mechanic. In games, the spread of the crosshair is an indication of the accuracy to expect out of the firearm at that moment. It holds true that firing a gun while running is less accurate than firing while standing still, as moving adds another variable into the accuracy equation. It is also true that firing in long bursts is less accurate than firing in small bursts, as recoil will drive the firearm off target. In game, this mechanic helps to promote firing while standing still (most games also further reward crouching and laying prone with an additional accuracy bonus). This helps to discourage the type of run and gun combat from early shooters such as Quake, creating an atmosphere of more tactical combat. Modern games often have differing levels of crosshair expansion for different guns, which encourages certain play styles for those guns. Sniper rifles, as in Call of Duty 2, are much more dramatically affected by crosshair expansion than are submachine guns. This discourages snipers from shooting while moving, and encourages them to stake out places in the map which are particularly conducive to sniping. Close range weapons are often less effected by crosshair expansion, which permits fast shooting and moving, but suffer from larger initial crosshair size, which makes their weapon too inaccurate to use at long ranges.