Any alien who at any time after admission is convicted under any law of purchasing, selling, offering for sale, exchanging, using, owning, possessing, or carrying, or of attempting or conspiring to purchase, sell, offer for sale, exchange, use, own, possess, or carry, any weapon, part, or accessory which is a firearm or destructive device (as defined in section
921
(a) of title
18) in violation of any law is deportable.