The U.S. imports ammunition from more than 30 countries. Russia is the top exporter of ammunition to the U.S., according to Small Arms Analytics. Between 2012 and 2017, Russia supplied Americans with more than 4.7 billion rounds. Mexican companies supplied an additional 2.2 billion rounds during the same period. Doing so will probably encourage more ammunition production in the U.S., which would be more easily subject to regulation.

Source: Los Angeles Times March 26, 2018 11:37 UTC