The National Instant Check System (NICS) performs a check when people buy firearms from federally licensed dealers in the United States. It is also used to perform background checks on people applying for firearm carry permits in those states where such permits are required or offered by law. As there are now over 15 million carry permits in the United States, and firearm sales numbers are in the 10 to 20 million range per year, you can see that the number of NICS checks is not a perfect fit for the number of firearms sold. One of the reasons...