Re: Lead Bullet Cores
There's no denying the momentum and impact of the anti-lead movement. I suspect each company will find alternate ways (materials) to jump the hurdle.
From a ballistic performance point of view, those materials that are more dense than lead will have a leg up, provided the material is 'workable'.
Lead really is a uniquely perfect material for bullets. Inexpensive, swage-able, dense, homogeneous. Only influences outside of physics will move core material away from such a perfect element.
You can possibly use what's happened with shot shells as a crystal ball for what might happen with rifle bullets. I may be foggy on the details, but here's how I remember it...
When lead was banned for waterfoul hunting, steel was the first commonly used replacement. It sucked because of the low density. It just didn't kill like lead. Copper shot was better, but still not as good as lead. Now, many years later, there's bismuth and heavyshot which are on par, or better than lead in performance, because it's equal to or greater in density. They do cost several times as much as lead but they get the job done.
One big difference between the challenge for shotshells vs rifle bullets is the burden of precision.
To answer your question, I think if/when lead is banned for sporting arms use, I think all the companies will pursue many different options for replacement. After a lot of time goes by, the cream will rise to the top and everyone will gravitate toward the best solution, all things considered. If the shotshell market is an indicator, cost will not keep shooters from buying a less or equally capable product when it's their only option.
Of course, the above is just my opinion of how it might happen IF lead is ever banned. I hope it never comes to that.