Unfortunatly we are not allowd to carry handguns for self defence in Australia. If we could though...

.22!!! It is the easiest to shoot due to low recoil. All self defence happens at very close range and at 10 metres a .22 will do plenty of damage to said target. If you miss with a big cal handgun then you want to be able to make a very quick follow up shot and you are going to get a follow up shot in a heck of alot quicker with a .22 than you will with any other cal. Just remember this, a .22 bullet that hits will always do more damage than a .50cal bullet that misses!!!

M82A1