I'd like to preface this by saying that I'm neither a firearms expert, nor am I opposed to legal, controlled ownership of weapons in my country.
However, I take issue with the idea that assault weapon is anything but a value-neutral description of the purpose of those types of weapons. An assault weapon is a weapon with a high rate of fire, designed for use by soldiers during combat, in order to kill large numbers of people indiscriminately. It is true that a firearm is not offensive or defensive, but for the intent of it's operator. But ignoring that technological advances in weaponry cause them to have a higher potential for abuse seems convenient only for those interested in owning such weapons.
Furthermore, the definition "Any type of firearm that could save your life in an emergency." seems so vague as to be totally useless. Could a .22 target pistol save your life? Certainly, in some situations. Could a grenade launcher? I'm sure that once in a great while, yes. What about an M-1 tank? A slingshot?
Now having said all that, I do agree with Draeis' point that penalties for use of a firearm for criminal activities should be uniformly severe--for the same reasons that "Basic Self Defense Gun" is vague. Any firearm, no matter how underpowered or overpowered, could be used to do what firearms are designed for: kill.
I also think that recognizing the increased potential for greater abuse by technologically advanced weaponry requires stricter controls on said weaponry, and that those who cry "my rights" ignore that the rights of the individual must be weighed against the inherent potential for infringing on the rights of others with certain devices and technology.
Consider: would it be within my rights to construct an atomic weapon on my property? Even if a mishap would destroy, not just my property and family, but the property and families of everyone in town?
Contrariwise: there are people who are qualified to own high-powered weapons. I believe this issue is best handled by greater controls, better education, and stricter rules for determining who is qualified. The all-or-nothing stance of pro-firearms groups incites widespread opposition because it ignores something that is apparent to anyone who has ever fired a gun. They are dangerous and deadly.