When I was in the military I was always legaly a resident of the state I enlisted in. I wanted it that way because Illinois didn't take taxes out of military pay. However, I could get a drivers license from what ever state I was stationed in and make it legal to buy firearms in that state without changing my legal tax status. Residency for tax purposes and residency for buying firearms can be seperate. When I got out I worked overseas and was legaly a resident of a foreign country for tax purposes [no income tax that way] but I could still buy guns in florida where I kept a home and drivers license.