The latte grande at the Starbucks in Tysons Corner, Va., must have seemed extra steamy last month when two college students bellied up to the bar packing pistols on their hips, as casually as if they wore cellphones. Someone called the police, who confiscated the handguns and charged the students. But wait: the Catch-22 in Virginia's enfeebled gun control laws has kicked in. Sure there's a state law against carrying loaded firearms in public. But the lethal fine print defines "firearm" as a 20-round-plus assault rifle. So smaller weapons, like the .22-caliber and 9-millimeter pistols the students flaunted in their...