The problem I see with the training and law abiding citizens arguments are that most of the mass shooters we have seen recently knew a great deal about their weapons, and were law abiding citizens.

Until they weren't.

I have always found them to be weak arguments.

I also find most of the home protection arguments supporting assault weapons weak. People don't need semi automatics that can fire off 100 rounds without reloading to protect their home. They also don't need an arsenal to protect it. Those are just excuses to own lots and lots of toys, and prop it up with the constitution. It won't hurt people to own a few less of a particular kind of toy.

Or any, of some.