The tax stamp could easily be restricted to be spent in waterfowl enhancement only. BATF already is use to special taxes like for full auto guns and that goes back to 1934 as I recall. Do we just amend it so lead shot on waterfowl sing black powder if needed. Just get your foot in the door. RST could make a run of black powder ammo for the first year. Start small, be honest about it and make it like a reenactment of how duck hunting was a hundred years ago.
I'd pay $100.00 a year to use lead shot in my doubles. I don't want it tied to just one gun because for all my hunting needs I use several guns. A100/yr fee is nothing when you figure out all the other associated cost of duck hunting. You have nothing to loose. It would be voluntary. Like paying a hundred bucks for the right not to have to use more expensive ammo and enjoy our old doubles at the same time. Hell if I could get a lifetime permit I'd pay ten grand for myself and my sons.
And calling me a liberal is like calling Al Sharptin a white supremest. I was lol when I read that. My wife who is much closer to one was also.