Your unit is a Human Canon Tower
The Cannon towers ammo is a variable called ammo set to ammount of ammo, i made 5 in my example map!
Events
Unit - (the Cannon Tower) is issued an order targeting a point
Conditions
Maybe? Dunno yet!
Actions
Unit - Order (the Cannon Tower) to stop (didn't work, dunno what went wrong)
If (ammo Less than or equal to 0.00) then do (Unit - Kill (Triggering unit) else (do nothing)
Set ammo = (ammo - 1.00)
Sorry, wrong place, please delete now!