WHY? Don't feed into the hype about lead's toxicity. A solid brass bullet would NOT expand no matter what you do to it. It's too hard and tough to use a hollow point or some other means to make it expand.
If it's for use on dangerous game. there's copper solid bullets available that do the job quite well. If that's not enough, then there's solid bronze bullets, but be prepared to pay 10 bucks apiece for them. To say nothing about what running brass or bronze bullets down a barrel would do.
Pouring molten brass into an aluminum mold would result in a puddle of aluminum and brass on the floor. I'm not sure if molten brass would even flow through a sprue plate, then there's the problem of shearing the sprue loose from the bullet, if cast in an iron mold.
The more people I meet, the more I love my dog
They're going to get their butts kicked over there this election. How come people can't spell and use words correctly?