Green’s Dictionary of Slang

cap n.2

(US) a bullet, a shot.

[US]Robert Johnson ‘32-20 Blues’ [lyrics] She got a .38 special but I believe it’s most too light / I got a 32-20, got to make the caps alright.
[US] ‘Mexicana Rose’ in D. Wepman et al. Life (1976) 42: I dropped him with a cap from my Colt .44.
[US]E. Torres Carlito’s Way 8: Cap hit him on his belt buckle.
[US]R. Shell Iced 60: Mother-fucka stop that yellin’ or I’ll put a cap up yo’ ass!!!
[UK]Indep. on Sun. Travel 16 Jan. 1: You f*** with me; I put a cap up your ass.

In phrases

bust a cap (v.) (also bust caps)

(US) to fire a bullet.

[US]C.H. Smith Bill Arp 118: He rode up to the militia and pulling out his repeater, exclaimed, with uncommon gravity, ‘Lay down, meelish, I am going to bust this cap’.
New Orleans Daily Democrat (LA) 25 July 1/3: Somebody asks ‘where are the Bucktail Rangers?’ and echo answers ‘Lie down melish, I’m gwine to bust a cap’.
Staunton Spectator (Staunton, VA) 12 May 1/5: But when the cannons boom you hear the cry, ‘Lie down, militia; I’m going to bust a cap’.
[US]Nat. Trib. (Wash., DC) 21 Dec. 5/4: ‘I’d like awfully well t’ bust a cap at that brash young Lieutenant, afore he gets clean away’.
Pensacola News Jrnl (Pensacola, FL) 6 Jan. 4/4: Leo Turner, a mite of a negro boy, stood up for Julius Underwood, another pickaninny, to show him how to ‘bust a cap’ on a small ‘unloaded rifle’.
Galveston Dly News (Galveston, TX) 11 May 6/5: It must be rather binding on the American soldiers at El Paso to have to stand in ranks and watch the battles on the other side of the river without being allowed to ‘bust a cap’.
Palmyra Spectator (Palmyra, MO) 2 Feb. 9/2: If I was goin’ up to Dixon to shoot Chrischuns I’d never bust a cap on that kind of a man.
Denton Record-Chron. (TX) 24 May 5/7: Frank Hamer, strapping former Texas Ranger, leader of the ambush—’I hated to bust a cap on a woman, especially when she was sitting down’.
Tallahassee Democrat (Tallahassee, FL) 20 Jan. 3/1: ‘’Sno use, Pickles, the boys sure must bust a cap and burn powder and if the game is sorter shy then they soothe their restless souls at the traps’.
[US]Arizona Republican (Phoenix, AZ) 23 Dec. 38/2: I was up to Roosevelt over the weekend for some goose hunting [...] but we never got to bust a cap.
[NZ]R. Helmer Stag Party 85: Why bust a cap when you can do it a cheaper way?
[US]O. Hawkins Ghetto Sketches 12: Haul ass ’less you want t’ get a cap busted in it!
[US](con. 1930s) C.E. Lincoln The Avenue, Clayton City (1996) 151: Vernon steady bustin’ caps up they ass with ol’ Hargis’s thirty-nought-thirty.
[US]D. Woodrell Muscle for the Wing 202: Don’t bust that cap on me, man.
[US] Dr Dre ‘187’ [lyrics] Walkin’ down the streets of L.A. / Stay strapped cause niggas bust caps every day, yo.
[US]Ebonics Primer at www.dolemite.com [Internet] bust a cap Definition: to fire a weapon. Example: Fuck wit me and I’ll bust a cap in yo ass.
[US]G. Pelecanos Shame the Devil 76: [He] raps about busting a cap in someone’s head, fucking women in the ass, all that.
[US]Simon & Burns ‘More with Less’ Wire ser. 5 ep. 1 [TV script] I shoulda busted a cap in Pookie’s ass my own self.
pop a cap (v.)

to fire a weapon; to shoot someone.

[US] in B.L. Ridley Battles and Sketches of the Army of Tennessee (1906) 454: My men halloo out: ‘Lie down, Mr. Govan, Mr. Bate is now gwine to pop a cap’.
Lincoln Jrnl Star (NE) 6 June 5/3: A colonel cannot let his regiment retreat whenever the enemy pops a cap.
El Paso Herald-Post (El Paso, TX) 10 Aug. 5/1: He and his lieutenant dragged a Marine gun up to the front and then didn’t pop a cap.
[US] ‘Death Row’ in D. Wepman et al. Life (1976) 118: I popped four caps through his chest with my piece.
[US]T. Thackrey Thief 408: So, fuck him – I popped a cap.
[US]J. Wambaugh Glitter Dome (1982) 128: Schultz and Simon could never prove that on some occasion Samuel Billings hadn’t tried to pop a couple of caps at a cat or a rat.
[US]Tarantino & Avery Pulp Fiction [film script] 158: A cold-blooded thing to say to a motherfucker ’fore you popped a cap in his ass.
[US]Bynum & Thompson Juvenile Delinquency 290: The man popped a cap at cuzz while he laid a drag on a freak sitting on the benzo.
Online Sl. Dict. [Internet] pop a cap v 1. to shoot. 2. to kill with a firearm. (‘I’m gonna pop a cap into that bitch when I see her next!’).
[US]F.X. Toole Rope Burns 165: If some fool of whatever color was coming to kill him, he’d pop a cap in his ass in a heartbeat.
[Ire]P. Howard PS, I Scored the Bridesmaids 149: I’m gonna pop a cap in the mother’s ass.
[UK]T. Black ‘I Want Candy’ in Killing Time in Las Vegas [ebook] That bastard tries to bigfoot me one more time, I’m popping a cap in his wide old ass.
snap a cap (v.)

(US) to fire a shot.

[US] in S.C. Wilson Column South (1960) 218: He said, ‘To hell with the Yankees,’ and snapped a cap [HDAS].
[US]R.G. Hampton Major in Wash. City 155: He’s as game a man as ever snapt a cap.