Bullet size in much more critical in my testing than is hardness..Yes you need a bit harder bullet if you wish to speed or create more pressure with it.
I feel many hard cast bullets sold today are too hard.
Much reading on lead hardness .
Water dropped alloy with the right alloy will continue to harden up to about 2 week period.
Air cooled seems to gain 3-4 hardness numbers over that time span.
So if you are checking hardness the day of you will be off on the number a bit.
some links to read through. I am sure there are a million more. I have read a bunch of them.
I have not checked my alloy hardness ever..But I do know straight clip on wheel weight with nothing more added and water dropped will shoot fine in my 30-30 at 2000 fps and fine in my 6" 357 mag at 1376 fps for 170gr both gas checked and lubed
If I cut the alloy with soft lead by 50% it shoots fine in 45acp and all velocities and at 1,100 fps in 357 mag it is happy.
https://thefiringline.com/forums/archive/index.php?t-375283.html
http://www.lasc.us/heattreat.htm
http://castboolits.gunloads.com/showthread.php?67640-Effects-of-age-hardening-on-our-cast-bullets
I feel many hard cast bullets sold today are too hard.
Much reading on lead hardness .
Water dropped alloy with the right alloy will continue to harden up to about 2 week period.
Air cooled seems to gain 3-4 hardness numbers over that time span.
So if you are checking hardness the day of you will be off on the number a bit.
some links to read through. I am sure there are a million more. I have read a bunch of them.
I have not checked my alloy hardness ever..But I do know straight clip on wheel weight with nothing more added and water dropped will shoot fine in my 30-30 at 2000 fps and fine in my 6" 357 mag at 1376 fps for 170gr both gas checked and lubed
If I cut the alloy with soft lead by 50% it shoots fine in 45acp and all velocities and at 1,100 fps in 357 mag it is happy.
https://thefiringline.com/forums/archive/index.php?t-375283.html
http://www.lasc.us/heattreat.htm
http://castboolits.gunloads.com/showthread.php?67640-Effects-of-age-hardening-on-our-cast-bullets