Tree in farm-house where guns may be used (6,5)

I believe the answer is:

firing range

I'm a little stuck... Click here to teach me more about this clue!

'tree in farm-house where guns may be used' is the definition.
I can't judge whether this definition defines the answer.

'tree in farm' is the wordplay.
'tree' becomes 'fir' (fir is a kind of tree).
'farm' becomes 'grange' (grange is a kind of farm).
'fir'+'in'+'grange'='FIRING RANGE'

Can you help me to learn more?

(Another definition for firing range that I've seen is " where guns are used".)

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.