In first person shooters, the player's accuracy is usually directly proportional to the amount of bullets the player is given.
Give the player 5 bullets to last the entire level, like in Condemned, And the player will want to make those shots count, only firing when they are assured that they will not miss.
Give the player a weapon with a small clip like a single shot weapon before reloading, but have an abundance of ammunition nearby, and the player will have decently high accuracy, but they are less worried about running out of ammunition so thier shots will be more careless.
Finally, If you give the player Unlimited number of bullets (Halo 3 chain gun turret, Resident evil 5, ect), and accuracy is usually throw straight out the hypothetical window, as the player only needs to "spray and pray" towards the general direction the enemies are with very few worries. Usually weapons that have unlimited ammunition are automatic (Machine guns), but can include other gun types. But regardless, unlimited ammunition destroys accuracy.
