Class A is air rifles, non self loading rimfires, shotguns other than pump or auto, Class B is Muzzle loaders & centre fires other than self loaders. You could defend yourself with a firearm but by god you would have some explaining to do. I was going bush for work one time and broke down and had my vehicle towed back to town while I got a lift. My car was stolen from the mechanics and I told the police there was a shotgun behind the seat I had been taking with me. Man was I put through the ringer. I was in the police station for 4 hours giving statements and if it wasn't for a common sense sergeant who knows what would have happened. One guy was set on cancelling my shooters licence. Our laws can be a pain in the arse but in a country full of do gooders it can be tough.