Green’s Dictionary of Slang

(US black) a shotgun.

1975		B. Greer Slammer (1977) 73: Level that gauge on those men.
1987		King Tee & Mixmaster Spade ‘Ya Better Bring a Gun’ 🎵 A brown Cutlass pulls up, they put a gauge to your head / They say, ‘(Get out your car) if you value your life.’.
1988		Ice-T ‘Drama’ 🎵 Gauges out the window, one lay across the roof.
1997		G. Sikes 8 Ball Chicks (1998) 221: Meany asked Candy what she was in for. ‘Possession of a gauge. A felony.’.
1998		Mayor’s Anti-Gang Office City of Houston, TX Street Gang Sl. / Gloss. 9 Nov.: gage Shotgun.
2015		P. Beatty Sellout (2016) 22: Some drive-by homie, representing some color, clique [...] can stick his gauge out the passenger-side window of a two-tone coupe.
2015		M. Dargg ‘Upsuh’ 🎵 Catch an opp watch him run guh / Young M dududu might hit him with the gauge.
2022		Digga D. ‘Noughty by Nature’ [Intro] 🎵 And that’s when I copped a gauge.