There is not a straight answer to your question due to variables such as how much expansion, expansion in what (bone, meat, soft organs), meplat size, etc... The typical cast boolit does not seem to expand much compared to high grade jacketed, but with a large meplat, you can still get the shock effect and they penetrate like a frieght train going through a Chevy!!
Hi Idahoe Joe,
Have you tried a dual harness cast bullet? That is standard ww soft on the nose and hard cast on the base.
It is not that hard, you can try a couple first and see how you go. All you need to do is cast your bullets and either water quench or heat (oven) harden. When the bullets are a few days old and have reached their designated hardness, grab a few and stand them in cool water up to the crimping groove, then heat the nose evenly with a butane type of burner and just when they start to change colour, stop and let them stand, until cool to the touch. The nose will have then returned to the original harness of your casting alloy.
Hope this helps.
1/2 pure lead, 1/2 wheel weights, and water drop these. This will give you a ductile projectile that will not shatter like linotype, but can still be driven to jacketed velocities. If you want extra expansion you could send your mold to get hollowpointed here http://www.hollowpointmold.com/.