Left 4 Dead Glitches

Fire an entire clip in 1 second
This will work with only the full auto guns, aka the Uzi submachine gun and the assault rifle. This works in 360 version and might work on PC.
  1. Equip the Handgun, hold down melee (LT) until you swing twice.
  2. While still holding down melee, switch to your full auto gun (Y) and hold down the fire button (RT).
  3. Keep holding down both LT and RT until you have held down RT for 7-10 seconds, then let go of LT only.
If done right, you will fire the entire full auto clip at once in a manner of 1 second, and the game registers as all the rounds being fired. This works really well for Tanks as long as you can hit them of course. If all 4 people can manage to do this on a Tank, he will be either dead or fairly close to dead within like 10 seconds.