They've identified the problem - hunters and fishermen.
This is round 2 on this merry go round.
An Official Journal Of The NRA | Departing USFWS Director Dan Ashe Issues Lead Ammo Ban
The US Fish &Wildlife Service tried this before. Dan Ashe, the suckass MFer that was appointed by Obama, on his way out the door after Trump was elected, passed a rule banning all lead ammunition and fishing tackle on federal land, or at least what was under USF&WS control. Total dick move to screw over hunters and fishermen.
Fortunately, Trump's pick for Secretary of the Interior squashed that on his first day in the position. I don't see anyone reversing this position anytime soon.