I have heard of loads as low as 40 gr of t7 3f being used on deer out to 100 yards with no trouble, but I think for me I would look at 60 gr of t7 2f being the lowest I would go with a 240 or 250 gr xtp. Hornadys muzzleloading chart shows 70 gr of t7 2f giving about 1600fps with a 240-250 gr bullet. That would give you around 850-950 fpe at 100 yards, plenty to take a whitetail.