Self-service meal? That's a blow (6)
I believe the answer is:
buffet
This clue is a double definition.
'self-service meal?' is the first definition.
(I've seen this before)
'that's a blow' is the second definition.
(thesaurus)
(Other definitions for buffet that I've seen before include "Bang - refreshment counter" , "Self-service meal; strike" , "Batter - help yourself meal" , "Help yourself table" , "Light refreshments - strike" .)