There are three sets of regulations here.
First, the Federal Law. Per FOPA '86, there is no Federal restriction on buying a long gun out of state, face to face, from an FFL Dealer.
Second, State Law in the state of purchase. The state where you wish to purchase a long gun may have a restriction (generally a residue from the original GCA '68, where contiguity was required, many states copied that part of the Federal Law) on purchaser's state of residence. Here in Ohio, for example, while Federal Law permits a NJ resident to purchase a rifle, Ohio law requires that the purchaser be a resident of a contiguous state. We (
Fulton Armory) run into this when we have our store at Camp Perry during the National Matches.
Third, State Law in the state of residence. Purchasers of firearms who are residents of IL, MA, CA, and, from what I read in this thread, NJ,
inter alia, have their state law with which to contend. FFL Dealers are required to sell to out-of-state purchasers only in a manner consistent with the puchaser's state of residence. Since the requirements of some states are arcane, and the requirement to be
a courant with all the relevant state laws of other states (the BATFE publishes an annual book of state regulations to assist FFL holders in these matters) is burdensome, some dealers simply won't sell to out-of-state residents, particularly to those from states with difficult requirements. I've run into dealers who refuse to honor a C&R FFL because I was from out-of-state!
As noted previously in this thread, prospective purchasers should enquire of their local authorities as to what procedures they must follow or documents they must acquire, and also enquire of the vendor to what requirements in his or her state out-of-state purchasers must conform.
It was a whole lot easier when you could send a postal money order & get your rifle delivered by Railway Express. Of course, that ended forty years ago this year.
Regards,
Walt