Pretty much you can go to just about any state except for California, New York, Washington state, Maryland, Illinois, and handle a firearm. As far as owning one and buying one, I don't think you'd be able to do that without meeting certain immigration and federal requirements. There might be exceptions and what not (I don't know all the details as I didn't look into laws regarding non-US citizens owning firearms), but the general answer is NO. So if you just go to the US to buy a firearm, then you would not be able to get one. Sorry :(