I don't care if it's sin. Guns kill more people and way faster than knives do. There are different kinds of knives for different purposes. Guns are used for one reason and one reason only: to kill. I'm glad we have a right to bear arms, but I hope you are pretty darned aware of the responsibility you have when you carry one. You could end up accidentally shooting someone who was just reaching for their phone.
So what if criminals are going to avoid the law? Should we not have laws then? Should we just let anarchy erupt?