Weapons rule India out (8)
I believe the answer is:
ordnance
'weapons' is the definition.
(term for artillery)
'rule india out' is the wordplay.
'rule' becomes 'ordinance' (ordinance can mean an order or rule).
'india' becomes 'i' (phonetic alphabet: alpha, bravo, charlie etc.).
'out' indicates named letters should be taken away.
'ordinance' with 'i' removed is 'ORDNANCE'.
(Other definitions for ordnance that I've seen before include "Military supplies and materials" , "Cannon; munitions" , "Survey may follow this" , "guns etc." , "Anne Cord is in military supplies" .)