Little bit and a lot for mass killer (4,4)

I believe the answer is:
atom bomb
'mass killer' is the definition.
'atom bomb' can be an answer for 'killer' (I've seen this before). I'm not certain of the 'mass' bit.
'little bit and a lot' is the wordplay.
'little bit' becomes 'atom' (tiny particle).
'and' is a charade indicator (letters next to each other).
'a lot' becomes 'bomb' (I have seen 'lot of money' mean 'bomb' so perhaps 'lot' could also mean 'bomb').
'atom'+'bomb'='ATOM-BOMB'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for atom bomb that I've seen before include "Weapon of mass destruction" , "Explosive device" , "can be a big killer" , "The first one was dropped on Hiroshima" , "Destructive weapon" .)
