Urgent supply to prop up country wanting vital piece of military hardware (6,3)

'country wanting vital piece of military hardware' is the definition.
I don't know anything about this answer so I cannot judge whether this works.

'urgent supply to prop up' is the wordplay.
'supply' indicates anagramming the letters (in a supple way).
'to' means one lot of letters go next to another (I've seen this in other clues).
'prop' becomes 'rut' (I can't explain this - if you can you should believe this answer much more).
'up' shows that the letters should be reversed in order (in down clue: letters go upwards).
'rut' back-to-front is 'tur'.
'urgent' with letters rearranged gives 'retgun'.
'retgun' after 'tur' is 'TURRET-GUN'.

Can you help me to learn more?