The Right to Bear Arms Prevents Slavery by the Government

I believe that the second amendment is important to the U.S. but where do we draw the line? Is it a right to own an assault rifle? If so should we be able to own missiles and explosives? I think we need to use common sense when considering gun control and realize that there is not a slippery slope: If we outlaw assault rifles, it does not follow that the next step will be to outlaw shotguns.