Clark,
When casting the balls, did you drop them into water to cool?
If the hardness is different from the ingot, I can see surface tension giving a different reading if cast into water, but like you, I am at a complete loss as to how hardness can change otherwise.
The Lee alloy tester needs a fairly large, flat surface for testing. That means filing the surface of a/the balls for testing.
Lead alloys will not harden when dropped into water, unless they contain both antimony and arsenic, although the arsenic
content is minuscule, but necessary. Lead shot has enough arsenic to harden if quenched or heat treated, as-do old style
alloy clamp or crimp-on WW's.
As noted, I cannot figure it out either, Richard.
The only way would be if an alloy bar of lead was introduced into the pure lead melt.
I also do not understand why THIS barrel is an anomaly as to loading snug patched balls.
Even an 8 brinel ball should be loadable with a .020" patch and .530" ball.
I was loading .682" WW balls in my .69 with the 12 oz. denim - THOSE were bloody tight, which is why I purchased the .677" mould. Those
load just fine with the 12oz AND 14oz. patches, I measure at .030" and .034"(calipers compressed).