Bullet fit is everything, then what job do you want the bullet to do.
I was lucky to find some babbit metal at the scrap yard, many years ago. When cleaned uo the metal had a reddish cast, I'm guessing there's copper in it.
The metal made the prettiest, hardest, most accurate cast bullets I ever shot.
Jim


"Whensoever the General Government assumes undelegated powers, its acts are unauthoritative, void, and of no force." --Thomas Jefferson