From Guns.com:

P.W. Arms, Inc., a wholesaler in Redmond, filed suit against the Bureau of Alcohol, Tobacco, Firearms and Explosives in a Seattle federal court on Dec. 18. The lawsuit alleges the ATF incorrectly classified the ammo 7N6, a 5.45x39mm rifle round, as “armor piercing” and in turn prohibited it from importation after permitting the company to do so.