You don't need 'hard' alloy for 1,100 fps.
I run nothing 'harder' than wheel weight alloy, even in rifles. Most handgun loads - including max pressure .44 Mag - rarely see an alloy 'harder' than 'Isotope Cores', roughly 10-11 BHN.
This may help:
https://www.youtube.com/watch?v=RzbHtUwrTvQ