Green’s Dictionary of Slang

1. (US black 20C+) usu. in pl., a pistol, a gun [pop v.¹ (1b)].

1750		F. Coventry Hist. of Pompey Little (1785) I 40/1: [I] borrowed a friend’s horse, bought a second-hand pair of poppers [...] and away I rode.
1764		Foote Mayor of Garrat in Works (1799) I 186: I don’t much care for your poppers and sharps.
1823		‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc. 138: A Popper — a gun — pistols are the poppers.
1833		‘Jerry Abershaw’s Will’ in Fal-Lal Songster in Spedding & Watt (eds) Bawdy Songbooks (2011) III 16: Take these poppers and this fourteen inch chive, / They are bussom friends vhat werry seldom fails.
1836		H.M. Milner Turpin’s Ride to York I vii: Damn the popper!
1848		Flash Dict. in Sinks of London Laid Open.
1905		H. Green Actors’ Boarding House (1906) 234: She had a ‘popper’ with her, and he had a long shotgun.
1911		Gem 30 Sept. 17: But fists are no good against a popper like that.
1944		‘Jiver’s Bible’ in D. Burley Orig. Hbk of Harlem Jive.
1996		Eble Sl. and Sociability 83: A single term, bill, means ‘knife; and popper means ‘gun’.

2. (US black) in pl., the fingers [? one ‘pops’ them in time to music].

1947

M.H. Boulware Jive and Sl.

3. a gunman.

2000

F. Kellerman Stalker (2001) 412: She doesn’t know diddly about hiring a professional popper.