You may find the information you need at this link.
http://www.hooyou.com/news/news070408gun.html
What does an alien need to know about Federal Gun Laws?
Jian Joe Zhou, Attorney at Law
On Thursday, June 27, 2008, the United States Supreme Court delivered a historic ruling on the rights of an individual to own guns for self protection purposes. In its decision, the Court ruled that the 2nd Amendment to the US Constitution protects an individual’s right to keep a firearm, and the Court struck down a Washington D.C. law banning the possession of handguns. The controversial decision has sparked debates because it expands previous interpretations of the 2nd Amendment that understood the right to bear arms as a collective right that was only constitutionally protected when related to military service. This new ruling, in contrast, upholds the rights of hunters, marksmen and other individuals to possess firearms. Many anticipate that, in light of this new ruling, many state and local gun laws will be challenged in court and limitations on gun ownership may be reduced.
While the Supreme Court ruling may loose restrictions on firearms control for citizens and legal permanent residents, there are still state and federal regulations in place for nonimmigrant aliens who wish to buy or sell a gun in the US. At Federal level, in February of 2002, the U.S. Department of Treasury, Bureau of Alcohol, Tobacco, Firearms, and Explosives, announced that individuals who are not in valid status or who are in nonimmigrant status cannot buy, sell, or possess a firearm or ammunition in the US. The Department of Treasury’s announcement is a clarification of the implementation of the Omnibus Consolidated and Emergency Supplemental Appropriations Act of 1998 which amended the Gun Control Act of 1968. There are exceptions to this rule, but nonimmigrants should be aware that firearms violations may have lasting immigration implications.
In general, nonimmigrants (such as those who hold F, H, J, O, L status in the US) cannot purchase or possess firearms (including handguns and long guns) in the United States. However, some exceptions apply that allow nonimmigrants to purchase and own guns.
To qualify for an exception, an alien must first establish that he/she is in valid status and has an “A” number or Admission number (I-94 number) issued by USCIS. A nonimmigrant alien must also prove that he/she has been a resident of his/her home state in the U.S. for at least 90 days and will continue to live in that state. Nonimmigrants who wish to purchase handguns will also be required to purchase their firearm in their home state. Nonimmigrants who would like to purchase long guns may do so in any state, provided they meet the local regulations where he/she purchases the long gun.
Once these qualifications have been fulfilled, aliens must prove that they fall within one of the following categories:
Go to the link to read the rest.
========================================================================
The following was posted at another forum, however, this post is from 2004. I suggest you try to investigate this on your own at:
http://www.atf.gov/firearms/faq/faqindex.htm Go to section 'R'.There may be additional areas of interest for you, but I can't do it all for you. 
More "Magic words":
Residing for at least 90 days. Hunting License.
======================================================================================
(from a 2004 post.)
(A15) Q. May foreign visitors and other aliens legally in the United States purchase or possess firearms and ammunition while in the United States?
A. Nonimmigrant aliens generally are prohibited from possessing or receiving (purchasing) firearms and ammunition in the United States.
There are exceptions to this general prohibition. The exceptions are as follows:
nonimmigrant aliens who possess a valid hunting license or permit lawfully issued by a State in the United States;
nonimmigrant aliens entering the United States to participate in a competitive target shooting event or to display firearms at a sports or hunting trade show sponsored by a national, State, or local firearms trade organization devoted to the competitive use or other sporting use of firearms;
certain diplomats;
officials of foreign governments or distinguished foreign visitors so designated by the U.S. State Department;
foreign law enforcement officers of friendly foreign governments entering the United States on official law enforcement business; and
persons who have received a waiver from the prohibition from the U.S. Attorney General.
Significantly, even if a nonimmigrant alien falls within one of these exceptions, the nonimmigrant alien CANNOT purchase a firearm from a Federal firearms licensee (FFL) unless he or she (1) has an alien number or admission number from the Immigration and Naturalization Service AND (2) can provide the FFL with documentation showing that he or she has resided in a State within the United States for 90 days prior to the firearms transaction.
(A16) Q. Typically, who are "nonimmigrant aliens?"
In large part, nonimmigrant aliens are persons traveling temporarily in the United States for business or pleasure, persons studying in the United States who maintain a foreign residence abroad, and certain foreign workers. Permanent resident aliens are NOT nonimmigrant aliens. (Permanent resident aliens often are referred to as people with "Green Cards").
