Full background checks are required in all the states i've lived in. The only way you can walk in a store or how about a reputable store and buy a gun and take home right then is if like me you have your concealed weapons permit. Hence forth you have had full extensive back ground done. Otherwise a back ground check is done...you wait 3 business days and if you are approved you get your gun.
Currently, federal law only covers firearms purchases made from a licensed firearms dealer although some states require that ALL firearms purchases even between private parties be transacted through a licensed firearms dealer to close up the gaps.