I am unfamiliar with the Saeco scale, but on assumption your read is correct, the Brinell 8 should work. That's roughly equivalent to 40:1 lead/tin alloy which is suitable for that class of cartridge and the pressures it works at with black powder. It is also about the same as CCI .22 RF bullets. BHN 11 is not far off wheel weight hardness which is generally set at 11-12 BHN depending on source.
If you are using smokeless I would steer the choice of alloy hardness based on your anticipated pressure, and expect the BHN 11 alloy to work ok-fine with that.
Absent specific knowledge of what your alloy mix is I would be inclined to take it easy and see how affairs develop. You can add some pure to the harder alloy and make it work most likely or may find that a dash of tin is your best friend. Tin lowers the surface tension of lead and provides both better fill out in mould but increased toughness as well. I don't cast bullets without it save for the pure lead slug gun variety.
Last edited by DigitalDan; 01/31/15.
