b-bomb, n. — Green’s Dictionary of Slang

b-bomb n.

[the explosive effects, ? var. on A-bomb n.]

1. (US drugs) amphetamine [abbr. Benzedrine].

1969		R.R. Lingeman Drugs from A to Z (1970) 43: B-bombs [...] benzedrine inhalers. Manufacturer [...] removed them from the market in 1949 after widespread abuse. The Benzedrine-impregnated wad inside the inhaler was removed and soaked in liquid to extract the Benzedrine.
1971		E.E. Landy Underground Dict. (1972).
2001		ONDCP Street Terms 2: B-bombs — Amphetamines.

2. MDMA.

2001

ONDCP Street Terms 2: B-bombs — [...] methylenedioxymethamphetamine (MDMA).