There is still lead in there with the silver. My guess is that you can load to somewhat faster velocities but not as fast as with copper jacketed bullets. Try them and let us know what you find.
I heard it won't kill werewolves. It just makes em yell...OWWWWWWWWWOOOOOOOO!Supposedly Oregon Trail owns a silver mine. Good bullets, but like Hombre said you can go a little faster with them, but I've still had leading if I pushed'em too much.
But as for the silver content, I'm still waiting for a response from them on my question of terminal performance on werewolves.