My range does a lot of skeet/trap/sporting clays. Birdshot is still easily available so I don't think it will hurt them too much.
Our clay target club is getting worried - there is no reliable source or lead shot, powder or primers - let alone factory target ammo -this is the busy season with the snow birds here - if he doesn't make his money now, things will be grim indeed. I reload for practice at his club. With supplies very low, I am down to once per week from 3X per week - and I am not the only one