Where did you get that 9.1 figure for the 30-1 alloy?
See Los Angles Silhouette Club
note here about 1/3 down the page/left side. I tend to reference these guys for any number of reasons and have found them to reflect the True Cross on any number of Cast Bullet subjects.
See also PnJ Resources
I was also concerned that the BHN of the 30:1 alloy was truely soft -- until I baselined against the pure reactor-shielding lead I've been carrying around since my misspent youth. That
measurement told me waht was going on and how to "fix" it.
If there's a better BHN alloy listing that those cited above, I'll gladly use it.