No one would be able to shoot anyone anymore. Being dead by a knife is being just as dead if you are killed by a gun. Besides, knives are quieter, therefore letting me sneak up on more people before I kill them. Now let us outlaw knives. And don't forget poisons.
Veterinarians have lots of good stuff.
And how about plant and garden stores. Taking some good insect poisons and putting it into the water pipes at school would probably make my point without firing a shot. And within a couple of weeks, I bet I could make an automatically loaded, miniature bow gun. Great for hunting, too. Many of the complaints and tragedies associated with guns is that of gun accidents.