Range of muscle displayed in David Gilmour's action? (8)
I believe the answer is:
spectrum
'range' is the definition.
(a spectrum is a range or variety)
'muscle displayed in david gilmour's action?' is the wordplay.
'muscle' becomes 'pec' (pectoral muscle).
'displayed in' means one lot of letters goes inside another.
'david gilmour's action?' becomes 'strum' (David Gilmour is a guitarist).
'pec' going into 'strum' is 'SPECTRUM'.
'of' is the link.
(Other definitions for spectrum that I've seen before include "Range of colours, opinions etc" , "lot of colours" , "Range of colour produced by a prism" , "Crumpets (anag)" , "Crumpets can provide the full array of colours" .)