Originally Posted by empire88
pull the trigger once and a gun shoots 2+shots.
Think of the way your gun monitors the trigger sort of like a heart monitor, you've got the flat line with big spikes (trigger pulls) and little spikes (background "noise") a gun begins to "bounce" when the trigger is adjusted to be so sensitive that those little spikes are interpreted as trigger pulls. The gun will begin to add shots, providing an effect sort of like ramping, only not controllable by the user.
There is also what we call "Mechanical Bounce" which is basically when the trigger is adjusted to be so short and so light that the recoil of the marker firing is enough to trip the trigger system extra, unintended, times.
Bounce can be very dangerous, guns that are poorly set up can "run away," essentially firing until they are empty after the first trigger pull. Considering that the first shot can sometimes be initiated by something as simple as someone bumping the marker too hard this can create quite a hazard. Also there's the issue of overshooting on the field with a gun that can't necessarily be controlled, or stopped after an opponent has been marked.