In OZ pigs were not indigenous and are exclusively domesticated pigs that have gone wild. Apart from crocodiles in the northern part of Australia, there are no predators that keep them in check and without regular shooters helping out, they become a feral nuisance that kill stock and damage property. Long ago I have seen guys try and hunt pigs with .22 rifles which are of little value with a bigger boar, a .303 does the job most of the time but if you want to stop them first shot, a big bore gun is the way to go.
I used to use a .44 magnum Winchester that did the job fine. A .44 Marlin was better but were a nasty noisy thing to use and I have seen guys use solids in a 12# shotgun but they really kick and will sit you on your butt if you don't know how to use them. Main problem is folks who have only ever lived in urban environments have no idea of the feral animal problem in OZ and only think in terms of their own safety as they perceive it and the end result is drive by shooting in Sydney's western suburbs, armed criminals, drug dealers with exotic toys like Uzzis and the terrorist market who have things like RPGs and specialised assault rifles.
The people who need them are pissed around so badly that they no longer bother and folks on properties even when the jump through hoops to get the licences cannot hunt in adjoining national parks so they can never beat the odds of dogs, cats, pigs, horses, donkeys, camels and anything else much that are out of control.
