Ysterhout Dot Net
While the concept is still a thought experiment, define your goal of casting for big bore.
If your goal is to cast bullets to reduce the cost of range practice with your rifle, then this write-up can offer some light on a road already travelled.
It is possible to cast bullets for your .375, .416 and .510 big bore rifle at a small fraction of the cost of commercial bullets. At the time of writing, I can cast a bullet for three percent the cost of the commercial factory bullet.
It is also possible to get the cast bullet weight and velocity, or power factor, sufficiently close to factory ammo so that in the field with factory bullets, the difference is barely noticed.
It is a very tricky business to get lubricated lead bullets to perform adequately. A library of books have been written on the subject. You will not succeed on the first try.
There are as many ways to cast for big bore as their are bullet casters. I will describe the approach I took, and which worked for me.