Sorry, no chronograph or “real-life” data for you, but I don’t think a 240 gr SP, at less than 100 yds, in the 1300-1500 fps range, should be a problem, for a whitetail deer.
Plenty of guys are taking deer with 10mm/41 mag/44 mag out of handguns, not to mention the muzzleloader hunters.
My brother’s first deer was taken over 30 yrs ago with a Ruger .44 carbine, using Remington 240 SP’s.
Sure, you can find “hotter” ammo, but if the Fiocchi is grouping well, and your boy is shooting well, I wouldn’t sweat it, or at least not until you start thinking of stretching shots out to 125-150 yds.
