"Bust a Cap" origins?

Gansta slang for shooting someone is to ‘bust a cap on him’, or to ‘bust a cap on your ass’. I thought this was a relatively new invention, until I was watching “True Grit” last night and Robert Duvall’s character says to Kim Darby, “I don’t want to, but I’ll bust a cap on you if I have to”.

Now it occurs to me that this phrase probably originates with the cap-and-ball rifle. Was this something that came out of the civil war? Does anyone know?

Quite possibly. IIRC in Ken Burns Civil War series there was a letter from a Southern officer who made referencs to putting the smackdown on the yankees for dissing the confederacy.

ROTFLOL, Padeye!!!

WARNING!!! Completely not-necessarily-factual post follows:

I’ve always assumed it originated with capguns. You know, the little fake sixguns that opened up to load a roll of caps? And when you shoot, you pop a cap.

I haven’t ever thought it had any more profound origins than that…

I’ll have to look it up when I get home, but I have a large book, about 20 years old now, called “Chronicle of the 20th Century”, which provides a year-by-year account of events, in a newspaper-story-ish format. I recall reading the story about Bonnie and Clyde, in which a policeman at the shoot-out (1933, I think) is quoted as saying, “I hated to bust a cap on a woman, but it was her or us.”