Let's get one simple nationwide policy passed - to own, wield or otherwise use a gun anywhere in the United States of America you must posses a license that you can obtain only after taking federal firearms education classes and passing gun safety tests. We do this to drive. Let's do this to shoot. Keep it simple. Keep it safe.
The license can have different classes for different types of guns, just as drivers' licenses have different classes for different types of vehicles. Procedures to obtain higher classes will be more stringent. The national policy can be phased in to allow current gun owners to take the classes and obtain a license, or turn in their guns. After such a time possession and use of a gun without a license will be as illegal as driving without a driver's license.