May be , some of you knows it, this site is a manufactures of cast bullets , near kansas city ...
on this site is a very interesting article on Hardness-Optimized Bullets, how to define optimal hardness , function of pressure :
https://www.missouribullet.com/technical.php
After reading article on this site, i had made some calculation
MBC Formula is : Optimum BHN = PSI / (1422 x .90)
As I use 405 Gr (45-70 gvt) bullet from Lyman mold 457193, and powered by IMR 4198 powder,
we have this in reloading table:
Lyman give pressure value in CUP; but correlation whith brinell hardness is in PSI/
Lot of people say that there is no correlation between this to method of hardness test , but there is one :
excellent document about this, from denton bramwell:
https://www.shootingsoftware.com/ftp/psicuparticle2.pdf
So, from 18300 PSI to 27500 PSI with MBC Formula :
It is the reason why i had make some cast bullet in brn 15, and i will make the more of them in brn 18, to use a medium charge of powder, because i don't need max power to make holes in paper
if i decide to begin boar hunt (a lot , too much, near my village) i will reconsider that
i hope to found chronograph at range in september.
i had build some excel sheet about alloy, casting and so on.
if somebody want it, il will send it ....
See you soon...
BruniX