Colt M4A1 Carbine -- $3100

The M4 is the CT-only equivalent of the AK47. It is very powerful, yet it only uses 5.56mm ammo. It also costs quite a bit more. This is because it tends to be more accurate, and it also has a silencer you can screw on to it. When you press the alt-fire key, you will put the silencer on. Press the key again to take it off. This makes the gun much harder to hear, but it also reduces the damage it does, so I don't use it unless I really really think I need to be quiet. Again, the usual 30-round clip and 90 rounds in reserve. Definitely a good choice for a gun, which most people end up using.