a hardness tester is a great thing to have but there sure not exact. I had three at the same time. A seaco, lbt and cabin tree. All three would give differnt readings ont he same bullet. A hardness tester is more suited to comparing one batch of lead to another then they are to giving you the exact hardness of a bullet. I dont know if lynn is right about lead varying state to state. All mine has been from here in michigan and ive never had a batch test higher then 13 with any of my testers. Most is around 10-11. Water dropped i can get it up to 15 plus but not air cooled. My favorite alloy is 5050 mix of lineotype and ww and air cooled that usually goes between 15 and 17. If you truely have ww that tests at 15bhn you have some rare wws there. Ive been doing this for 30 plus years and have had testers for probably 20 of those years. I hear all the time that wws are softer now but ive really never noticed a differnce between my readings now and my readings 10 years ago. I think the major reason people claim this is they dont seperate the stick ons from the clip ons and these days theres a bigger percentage that are stick on because so many cars use alloy wheels and being that stick ons are pure it makes your final product a bit softer. My average if i dont seperate the stick ons is around 9bhn. So dont think because you own a tester that your readings are the wrote in stone right answer. Theres to many variables in what tester your using and your technique to be able to come up with the answer that is the absolute right one.
Yes, I suspect most measuring instruments have some variance. I know vertical micrometers I used to measure silicon wafers in the semi-conductor industry did. 3 gauges would give 3 different readings. Used to zero them on a optical flat. Somehow I don't thing a $50 Lee (or other) hardness tester is going to exactly align with the next one, let alone across brands. Unless Brinells are fairly broad units of measure.
I was just looking for a ballpark hardness for "WW Lead" in the event I resort to ordering a slab from Rotometals or whatnot. "WW Lead" seems to be a common standard of hardness among bullet casters.
What's driving the question is the recent purchase of some .30 cal. rifles.
I prefer to cast my own, but 2700 fps is generally considered to be way beyond plain base velocities. (That's why I have a 45-70 honestly... the extra bullet mass lets it get the job done at plain base velocities. With correspondingly round trajectory.)
I'm scratching my head and thinking... "Well really, .30 cal rifles are pretty much creatures of velocity, maybe they're not for me if I prefer to cast my own."
Gas checks, paper patching, etc. lots of extra steps. processes, parts.
When I note that the energy levels of cast bullets from .30 cal rifles at those lower velocities are in the .357 mag to .44 mag range, I find myself thinking... why not just carry a .44 revolver?
Granted GC's and harder alloys could change that quite a bit.