A heavy federal tax upon ammunition ( or gunpowder products ) for the dual purpose of 1) discouraging purchase of large amounts of ammunition, especially cartridges of enhanced lethality to humans and 2) generating revenue for law enforcement / first responders.
the tax will vary based on tiered categories:
1) little if any additional tax upon traditional and reasonable " birdshot and squirrel/rabbit " shotgun shells.
2) rounds/shells of increasing lethality - i.e.: buckshot, shotgun slugs, and small caliber rifle bullets
3) larger caliber rounds, higher power/velocity rounds.
4) exotic rounds with no practical purpose ( designed for killing humans ) and enhanced lethality subject to the highest tax tier. ( example assault weapon rounds, military rounds, handgun rounds...)