Here's a quote from the ATF FAQ page:
Q: May a person (who is not an alien) who resides in one State and owns property in another State purchase a handgun in either State?
If a person maintains a home in 2 States and resides in both States for certain periods of the year, he or she may, during the period of time the person actually resides in a particular State, purchase a handgun in that State. However, simply owning property in another State does not qualify the person to purchase a handgun in that State.
[27 CFR 478.11]
Whether the requirement that you OWN property is required is unclear. I believe if you rent and RESIDE there part of the year, you qualify as a resident. I believe a property ownership requirement would be unduly onerous and unconstitutional. This seems to indicate that ownership of property in a second state does not in itself qualify you to purchase a handgun in another state. You must actually be a resident there, although in other sections they do not state any minimum requirements for residency, just that you must "reside" there whenever you fill out the 4473. You might want to call your local BATF office for clarification but be sure they understand the above comment.