Hey, Kurt.
In a past thread we (some of us) were talking about various alloys used for PP bullets.
You mentioned having had fair luck with one or more antimonal alloys, and I mentioned I was using one, too.
As I recall, that was back in the fall, and you asked for a 'snowbanker' from me to compare with your own examples.
Well, snow was scarce last winter, with never enough depth for a shot. But our annual 'Easter Blizzard' dumped enough to cause all kinds of troubles.
Getting vehicles unstuck, and firing up generators to make electricity kept me from thinking about those bullets saved for a snowbank.
The deep stuff was almost gone when it dawned on me that I was missing the only opportunity ... so I grabbed the rifle and two rounds for a quick 'deposit'.
The first bullet passed through, but the second one stayed buried.
This is it, and I believe it to be 97% lead, 3% antimony, with a trace of tin. Hardness is 10.4 BHN using a tool that says 20-1 is 7.8 BHN. So, this is substantially harder than 20-1 lead/tin.
The naked bullet is 1.440", and the fired bullet is ten thousandths longer ... obviously due to the rifling being impressed into the patched to groove package.
So, no nose bump-up (slump) at all with an alloy this hard, but it still took a full impression of the barrel.