1980s film teaching gunmen about technology (9,4)
I believe the answer is:
educating rita
'1980s film' is the definition.
'teaching gunmen about technology' is the wordplay.
I cannot quite understand how this works, but
'teaching' could be 'educating' (educating is a kind of teaching) and 'educating' is found in the answer.
'about' could be 'a' (abbreviation in Chambers) and 'a' is found in the answer.
'technology' could be 'it' and 'it' is present in the answer.
A single letter 'r' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
(Other definitions for educating rita that I've seen before include "Comedy drama film (1983)" , "Willy Russell play" .)