And I don't think there is a requirement to produce a valid police-issued certificate when buying bullets either, is there? (Not FMJs anyway).
I think Your right infact anybody can go into an army surplus store and pick up a bullet belt made up of inert 7.62x51 cases and head to put around there waists. Although I'm sure the dealer I buy my FMJ's from checks that I have permision to posses live ammunition in that paricular calibre before he sells them to me.