I've been casting for 8 years or so, mainly pistol using COWW/SOWW (air cooled/water cooled), and just started mixing different alloys for my 450 BM.
My hard casts test at 22 BHN and my other alloy is Lyman # 2 (15.4 BHN). Loaded both using same powder (charge weights), primers, brass, sized to the same diameter, powder coated, etc.
Anyway, Hard cast grouped 2"-3" and the Lyman # 2 1"-1.26".....old news to the more experienced casters, but was eye opening for me.