INTRA vs. INTER
Intrastate: FFL not required
INTERstate: FFL required.
Examples:
INTRA: A police officer in Bloomington, Indiana has a Colt M6940 that he will get stupid Colt fanboy money from a lawyer in Lafayette, Indiana, with flowing hair, so much hair that he looks like Robert Plant. Lawyer sends cop money via priority mail, cop ships 6940 to lawyer's office. Lawyer, after combing his mad tangle of hair, so much hair, takes weapon home.
INTER: Jasper Lee Lee Longstreet Lee, Jr. of Gnawbone, Indiana, wants to buy a shotgun (non-C&R) from his second cousin's dog, Bitey, in Kentucky. The dog will ship the shotgun to Jasper's FFL of choice. Jasper will pony express a Western Union money order to Bitey. Jasper moseys into his FFL, fills out the 4473 and does the NICS check, unless Jasper has the new 5 year LTCH and is exempted. Jasper moseys homes with shotgun.