The most a 2315 100grain bullet point seems to take is another 100grains of solder, giving a 200grain point which seems to do the job (depending on your bow, draw length and poundage) if you need to go higher than that, you'll probably need to buy Pro Points
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Simon Terry was shooting fat aluminiums at Accrington and seemed to do ok ( 584 fita 18), not sure how much he increases the point weight by to get them to spine though.