They have been combined due to so many class specific weapons. First we'll start off with a little general weapon info, then get into specifics. With the ever ongoing balancing of classes what weapons they have and how powerfull they will be is ever changing. When we know something more specific, we'll be sure to let you know. Every class has some form of pistol or smaller secondary gun.
All pistols do locational damage.
A submachine gun and the sniper rifle also do locational damage. The weapons have recoil, accuracy and range. You will not be able to snipe with your pistol since the maximum range is not very long. The heavy machine gun can cover that range, but you must be crouched to shoot accurately with it. Some weapons are very inaccurate if fired while moving.