What are the firearms licensing requirements for non-U.S. citizens?

Permanent resident aliens or green card holders do not have to obtain an alien firearm license. They can purchase a hunting license, purchase firearms, and apply for a concealed pistol license.
In order to obtain an alien firearm license, a nonimmigrant alien residing in Washington must apply to the sheriff of the county in which he/she resides. However, if the nonimmigrant alien holds a current valid hunting license issued by a state, they do not need to obtain an alien firearm license (RCW 9.41.175 and See http://www.atf.gov/firearms/faq/nonimmigrant-aliens.html).