Shooting firearms, either for fun or practice, or in a violent altercation.

From a drug induced study session with several linguists somewhere in Arizona.
Bust-Cap, an exclusive language used when all other attempt at a covert language has failed, and the chick thinks she knows whats going down.

when da niggaz be bustin capS!!
shooting bullets from their Puny handguns. I will whip out my AT4 and blow all their gangsta azzes to hell. While my buddy snipes em from up in a high window

Used by gangstas it means "to shoot somebody"

To fire a gun (military slang from the days of percussion cap and ball firearms before the manufacture of individual cartidges consisting of a metal casing holding a bullet, gunpowder and a primer that fired when struck by a firing pin or hammer.)

This is not a new phrase as much of the Rap culture would like us to believe. Instead it is an old phrase to shoot someone. Reference to cap is a word for powder cap used in percussion guns popular in the old west. This phrase is used in the 1969 movie titled "True Grit" with John Wayne, Glen Campbell, Dennis Hopper and Robert Duvall.

A slang phrase referring to the posession and use to a certain individial of a firearm or any other object resembling a firearm that emits any sort of a projectile.