这种火器违法在移民法比较特殊。它属于拿绿卡之前犯了还可以办绿卡但拿到绿卡犯了就要驱除出境的类别

It is listed as a deportabel offense under INA 237
(http://www.uscis.gov/propub/DocView/slbid/1/2/65?hilite=)

But it is not listed as an inadmissible offense under INA 212 (http://www.uscis.gov/propub/DocView/slbid/1/2/31?hilite=)

For purpose of getting a GC, it is inadmissibility criteria not deportability criteria that will be used.