A quick rundown of every weapon
Pistol- Although somewhat effective against single unarmored zombies it is worthless agaisnt multiple targets. (Throwaway)
Magnum- VERY effective against unarmored targets, almost always 2 shots to the head for a kill.
Shotgun- A definite crowd stopper, but the reload is what was killing me, literally.
Sawed-off- While it has a faster reload than normal shotgun, it only carries 2 shots. (Throwaway)
Hunting Rifle- A great mid-game weapon, almost always a one-hit kill to the head and two-shot kill to the chest, but only effective against unarmored targets, the 1 round clip should also be considered.
Uzi- The second best gun in the game, combine a huge clip with rapid fire and a quick reload time and you have the best crowd stopped in the game.
Chainsaw- While it kills close-range zombies quickly it is just a waste of space, trust me. (throwaway)
M4A1- If you played CSS you probably went crazy when you found this gun. Unfortunately, it is not what it seems. While the reload time is faster than the AK, is has limited power against armored targets, and its accuracy could be better.
AK47- if this was final fantasy, this would be the Ultima Weapon. The AK has most Accuracy, only a slightly slower reload time than the M4, it is the most efffictive against armored targets, and it just looks cool! use the Uzi as backup and you are unstoppable
Hope this helps.