a cap 

A bullet

If he run his mouth to me one more time, I'll pop a cap in his ass

a cap by D x O x M x I March 14, 2018

a cap of weed 

when weed is in the bowl

a cap of weed we smoked last night was loud

a cap of weed by Hdbehfbruen October 6, 2019

imma pop a cap in yo ass 

An Agressive Slang, meaning the user is going to shoot someone

50cent "yo biatch! fuck yo nigga ass!"
DmX " Yo imma pop a cap in yo ass"
Joe Fagan "Damn, Thats Wack

imma pop a cap in yo ass by Joe Fagan February 18, 2004

pop a cap in your ass 

to shoot someone

Yo dawg imma go pop a cap in his ass

pop a cap in your ass by Justin Russikoff April 16, 2003

pop a cap in yo ass 

Ebonics for: "discharging a firearm into your body with the intent to cause grievous bodily harm"

nigga: yo son, you scuffed ma tims, imma pop a cap in yo ass

white man: ????

translator: he says because you have accidentally stepped on his costly Timberland footwear and caused small particles of debris to reside on said footwear, he will discharge a firearm into your body with the intent to cause grievous bodily harm

white man: :(

pop a cap in yo ass by Young Reezie December 13, 2009

Bust a cap in yo ass

To shoot an individual with a gun.

You bitch, getin all swoa, Im gunna bust a cap in yo ass!

Bust a cap in yo ass by James/Skeeter/Drex March 16, 2003

bust a cap 

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.)

We heard some people busting caps a couple of klicks up the trail.

bust a cap by jeff August 13, 2004