There's not a lot that can be done to fix this today, because cartridges were designed with lead projectiles, and guns designed around the cartridges. To get a heavier bullet, it would need to be a substantially bigger(longer) bullet, therefore not working in any gun.
A reasonable proposition is for a new cartridge to be designed around an all copper(or steel, whatever) bullet. It would take a lot of time to get adoption, though, unless the military uses it.