Measures ricochets blowing top (6)
I believe the answer is:
ounces
'measures' is the definition.
(ounce is a kind of measure)
'ricochets blowing top' is the wordplay.
'ricochets' becomes 'bounces' ('bounce' can be a synonym of 'ricochet').
'blowing top' means to remove the first letter.
'bounces' with its initial letter removed is 'OUNCES'.
(Other definitions for ounces that I've seen before include "Small weights in UNESCO" , "They're equal to about 28 grams" , "There are16 to the pound" , "Sixteen to a pound" , "Light weights in UNESCO" .)