The increase in the availability of so-called ghost guns is causing consternation among law enforcement, political leaders and gun regulation advocates. But what are they and why is the concern so high? Click here to read The Specter of Ghost Guns in California. Here is a primer: What is a ghost gun? Ghost guns are build-it-yourself firearms. You can order all the needed parts online, including kits with directions for building the gun, and have them delivered directly to your home.The parts have no serial numbers and buyers are not required to pass background checks. Once the gun is assembled,…