Didnt want to steal the thread that's open. SO here how I cast soft point bullets.
The big thing is to make a "metered" dipper to pour just the right amount for the soft point you want. I make mine from a case and bevel it so the low edge sets the amount needed and the high edge forms the funnel. A heavy wire with 3 wraps and a short tail with a longer end to fix in a handle. 3 wraps just smaller than the case, case pushed in and tail bent under to lock in place. A small wood handle. 3/32 brazing rod makes a nice shaft for this. File a 45* mouth with the low end setting weight. A 4 lb dipper pot is plenty for the noses.. Run this pot on the hot side around 800*- 825*. Keep the dipper in the pot. Here I use 40-1 lead tin, you want a little tin to aid in the bonding. A regular bottom pour with base alloy run around 750*- 800*.
Heat mould to temp on plate or in the base metal pot. pour in the nose metal from the dipper and quickly fill in the base from the bottom pour. Here a small stand to maintain the mould level and just slide under bottom pour pot. Done quickly the only thing you will see is the color change from base metal to nose. I hold the small dipper in my hand while filling the base metal in and set it back in the small pot while waiting for the sprue to cool. This makes some very nice bullets
Ive done 45 cal 500 grn round nose like this and they performed very well. on the lyman 458125 (510 grn govt) almost the whole nose is 40-1 Bullets recovered from a wet sand back stop show good expansion with no nose separations.
The trick is to fill fast and before the nose completely solidifies so the base can bond itself to it securely. Your basically making a solder or weld joint where the 2 metals blend. The small stand helps in maintain the position of the blocks level and square. Once you get it down its a matter of finding the pots placement that works for you. I like them close together and my little stand is just a extension of the BP pots base so I can set it pour nose and slide under to fill base. I also pour a big sprue to keep it hot as long as possible aiding in the blending of the joint.
When right you shouldn't see a line at the joint just a slight color change
What might be interesting is one the hollow point moulds with pins and the soft nose poured to below the hollow points depth by .100 or to the band.