well first, a long gun is considered 18"+ and technically speaking there are NO LAWS against how you can carry a 16" AR15, whether that be in your car or in public. for a 18"+ you can carry it anywhere in your car, loaded or unloaded. in fact you can carry it in public concealed if unloaded and loaded if its not concealed. i wouldnt let them know you have it in your car if pulled over, it opens you up for harrassment and a pro longed stop while they stomp on your civil liberties and illegally run the serial number. the lower you can buy online, it just must be sent to an ffl dealer (gun shop).