Armstrong not needing a second to master new little piece of music (6)
I believe the answer is:
snatch
'piece of music' is the definition.
(I've seen this before)
'armstrong not needing a second to master new little' is the wordplay.
I cannot really see how this works, but
'a' is found in the answer.
'not' could be 'nt' (synonyms) and 'nt' is located in the remaining letters.
'second' could be 's' (common abbreviation) and 's' is found in the answer.
The remaining letters 'ch' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for snatch that I've seen before include "Few bars of music - grab" , "Grab hurriedly or violently" , "Deftly seize" , "Seize abruptly" , "Fraction of a number" .)