Green’s Dictionary of Slang

(US) a street gang with active fighters.

1959		H. Salisbury Shook-Up Generation (1961) 22: The most notorious of all the bopping gangs of New York, the Chaplains.
1962		(con. 1953–7) L. Yablonsky Violent Gang (1967) 65: I wanted a social club and then to protect ourselves against the bopping gangs that come around.
1969		S. Greenlee Spook who Sat by the Door (1972) 83: The Cobras overnight became a non-bopping gang.
1974		(ref. to 1950s) H.L. Foster Playin’ the Dozens 73: In the early ’50s we had the ‘bopping’ or fighting gangs with mass fights or ‘rumbles’ between gangs as they guarded their ‘turf,’ territory, or neighborhood.