The only options available for you in
NSW are target shooting or hunting. In each case you have to state that class A firearms are insufficient. Either due to distances / type of competition for target shooting
OR "humane" hunting of larger vertebrate pests for hunting. To support your application, you need to show membership of an "approved" club for target shooting and either membership of an "approved" club for hunting or permission letter/s from landholders.
The
Primary Producer category holds it's own problems in that any licence granted / firearms acquired on that basis can only be used for that purpose, on the nominated property. You also have to prove you're involved in primary production, ( i.e. derive income from it ), which, unless you're growing "special" herbage on your 18 acres, I doubt you'll get through that step. The possibility that in the future you may need a cat B to euthanize a horse isn't going to cut it with registry.