Basicly you have to make shooting a major hobby to get into firearms there. One must be willing to spend a lot of money outside of the pruchase of the arm, and self defense with an arm is against the law. One must legaly store the ammunition and firearm seperately and locked up. So if you are able to use it for self defense then you were illegaly storing it.
It is not something the average person can purchase "just in case" like in America, just like one would purchases a fire extinguisher.
Even the lowly pump action shotgun with a 6-8 capacity which is pretty standard for home defence in much of America is a nearly impossible to obtain class D license. A pump with less than a 5 round capacity is still a class C and very difficult to obtain. That is funny because in America that is often viewed as one of the least sinister of firearms. Even the fud types would be surprised.
Semi auto is too evil, pump shotguns are too evil, and even an airgun (pistol) is classified the same as a handgun!
This is partialy the result (in addition to knee jerk reactions over things like Port Arthur) of people who argue the right to sporting uses of arms and avoid the less politicly correct argument of shooting criminals intent on harm. Well it appears you have retained your "sporting use" of some arms in Australia, and that is about it.
We are lucky in America that the Second Amendment itself was created to protect arms for the purpose of using them against people (agents of the government) as discussed by the founding fathers when the Bill of Rights was created. They were not adding it to give people that right, but restricting the government from infringing upon it.
So it is pretty hard to twist that around into a right to "sporting" uses.
So our right already exists for a pretty radical purpose that makes uses like self defense seem pretty tame in comparison. Of course it is so radical that I don't think most people even realize it unless they actualy read the discussions of the founding fathers. I certainly would not have imagined a government would add a clause protecting weapons to be used against itself, and they don't teach that in grade school.
For a while I sat here and wondered what sort of awesome firearm a powerhead might be (and thus, why I should go get one). Just as I start to post I realize it's that nail driving thingy we buy at the hardware store in the time it takes to wait in line at the cashier. Ouch.
Actualy a powerhead is an underwater device which fires a cartridge to hunt and to kill things like sharks. However it does not work through the use of a bullet (although normal ammunition is often used so there is one fired) but rather the expanding gases propeling a jet of water rapidly enough to slice right through tissue in its path. Basicly muzzle blast + water. The powerhead is fired into the animal on contact either from a shaft a diver holds or sometimes attached to a spear propeled by a spear gun (which have very short range underwater.) The wound track created is almost entirely based on the pressure and the actual bullet is incidental. A blank cartridge tends to have about the same result.
Obviously these are designed stronger than a firearm barrel as they work on contact and with added water pressure. So they have to be designed to fire with a barrel obstruction as the norm. Thier design is very simple and many divers simply make thier own. It is basicly a thick pipe with a crude firing mechanism that fires when it is shoved into something and a mechanical safety that usualy has a pin that can be inserted and removed to ready the loaded weapon. The safety design is very important as the spare powerhead tips themselves are often kept on a diver banging around as they swim through the ocean.
So picture a single shot underwater firearm that is fired by jabbing it into something. Not a nailgun. Attached to a shaft people also refer to them as a "bangstick" sometimes. The powerhead is the actual mechanical portion of such a device.
