With 165 grains of black powder in the barrel, a .75-caliber Brown Bess flintlock musket like the ones the redcoats carried in 1776 can hurl a lead ball at a velocity of around 1,000 feet (305 meters) per second. Imagine what that can do to a human body. Now, imagine that it’s almost completely exempt from gun regulations. How can that be? Well, under federal and most state laws, many antique or replica guns aren’t technically considered firearms. In most places, even convicted felons can own them. “I suspect the average judge would be surprised to find that out,” says Second Amendment scholar and gun-rights attorney Dave Hardy, himself the proud owner of two Civil War-era long guns.…