Here is a hypothetical situation.
Jim, a resident from the State of NJ, is a member of the reserves and is on TDY (temporary duty) orders to another state (State X) for training that will last 4 months - 120 days.
Jim meets a resident of State X and is interested in purchasing that person's handgun. However, Jim is concerned that this sale may be illegal because it is not being done through an FFL of his home state.
Jim consults the BATF site for an FAQ reqarding this particular purchase and discovers the following:
http://www.atf.gov/firearms/faq/unlicensed-persons.html
Jim wonders what constitutes residency of a State according to the BATF and continues to read...
While Jim is not on PCS (permanent duty station) orders, he is on TDY orders for a period to exceed 90 days. On-post lodging is provided and specified on his orders so, therefore, he is considered to be a resident of that state because he will at some point reside in that state for at least 90 days.
Can Jim purchase a handgun in another state "as a resident of that state", and return to NJ without ever having submitted a permit to purchase (a handgun)?