You could water drop pure W/W to get its hardness up a little. Or use a quick burn powder like (bullseye) which would help hold your pistol's bore leading to a minimum. A really good bullet lube is a necessity when it comes to these high velocity bullets also.
Casting isn't all that hard to accomplish. Like anything else it takes patience. And some experimenting too. If you use aluminum molds. Don't forget to candle smoke the lower side of your cutter plate before using. (wax smoking helps to not let its sprue cutter plate gall the aluminum it slides back & forth over.) So skizzums here's a few tips/tricks to keep in mind that may come in handy.