it's 5 years.............you can read it hear, under §447.52 Import restrictions applicable to certain countries.........but here is the jist of it.........
(f) Applicants desiring to import articles claimed to meet the criteria specified in paragraph (e) of this section shall explain, and certify to, how the firearms meet the criteria. The certification statement will be prepared in letter form, executed under the penalties of perjury, and should be submitted with the application for an import permit. The certification statement must be accompanied by documentary information on the country or area of original manufacture and on the country or area of storage for the five year period immediately prior to importation. Such information may, for example, include a verifiable statement in the English language of a government official or any other person having knowledge of the date and place of manufacture and/or the place of storage; a warehouse receipt or other document which provides the required history of storage; and any other document that the applicant believes substantiates the place and date of manufacture and the place of storage. The appropriate ATF officer, however, reserves the right to determine whether documentation is acceptable. Applicants shall, when required by the appropriate ATF officer, furnish additional documentation as may be necessary to determine whether an import permit application should be approved.
http://www.washingtonwatchdog.org/documents/cfr/title27/part447.html
and before someone says, well it don't say anything about magazine..........read the defination for "Import List. The list of articles contained in §447.21 and identified therein as “The U.S. Munitions Import List”.
then go and read what that list has...........
http://a257.g.akamaitech.net/7/257/2422/05dec20031700/edocket.access.gpo.gov/cfr_2003/aprqtr/27cfr447.21.htm
then read this part:
category xxi--miscellaneous articles
Any article not specifically enumerated in the other categories of
the U.S. Munitions List which has substantial military applicability and
which has been specifically designed or modified for military purposes.
The decision on whether any article may be included in this category
shall be made by the Director, Office of Defense Trade Controls,
Department of State, with the concurrence of the Department of Defense.