First, I added one tablespoon of sulfur to 10 pounds of barely melted J.R. brand reclaimed shot.

Second, I added 0.8 pounds of Rotometals 30% antimony. Guessing that the reclaimed shot started out at 4% Sb, then the enhanced version would end up at 5.9% antimony. The bullets were oven treated at 470F and quenched in water. After aging approximately 2 weeks, the hardness today was 40.5 BHN (4mm, 60#) or 45.2 BHN (10mm, 150 kg), for a 6 - 8 increase in BHN compared to straight J.R. shot.

45 BHN would be great, but when I tried to duplicate that recipe recently, it did not increase hardness one iota over regular J.R. shot.

So I am trying again, doubling up on the Superhard enrichment. I took 9.88 pounds of the "bad" batch of "enhanced" reclaimed shot (ERS for short) and added 0.94 pounds of Rotometals Superhard. Assuming the ERS started out at 5.9% antimony, that should increase it to 8% antimony. For convenience, I'm going to nickname this double-enhanced reclaimed shot "DERS". I'll update this post as the data rolls in.

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Density = 2719 grains per cubic inch, compared to 2768 gr/ci for J.R. brand shot.

Density is helpful when evaluating an unknown alloy because it lets you estimate the percent pure lead. The 2719 density tells us that this double-enhanced shot is about 91% lead and 9% something else. That's reasonably close to the estimated value of 8% antimony. Possibly it is actually 9% antimony, or possibly it is 8% antimony and 1% various other trace metals.

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After 1 day: 43.6 BHN / 10mm, 32.1 BHN / 4mm

The 4mm test seemed suspiciously low so I went back and remeasured it two more times and came up with 32.0 instead of 32.1, woopeedoo. The reason I report both the 4mm and the 10mm test is it's a general trend for a 4mm test to read less than a 10mm test above 21 BHN. Below 21 BHN the 4mm & the 10mm read pretty close. I've yet to explain why the two tests diverge above 21 BHN so I report both and let the reader decide what it means. The 10mm test is closer to being "official" and its bigger indentation is far easier to measure, so I consider the 10mm test more reliable.

The closest thing I have to a theory explaining the 4mm / 10mm divergence is that the 4mm indentation is so small on harder alloys that it's effectively measuring the hardness of the "skin" while the 10mm test still penetrates past the skin. I can't understand why the skin would be softer than the core, but if for the sake of argument the skin were softer that could explain the 4mm test's lower numbers.

After 2 days: 43.0 BHN / 10 mm, 39.9 BHN / 4mm

As usual I made 2 indentations with the 4mm tester, and as usual both indentations measured the same, so the 39.9 BHN result was not a fluke.

After 3 days: 43.1 BHN / 10 mm, avg. 40.1 BHN / 4mm

This time the two 4mm indentations were different, one scored 36.5 BHN while the other scored 43.8 BHN, for an average of 40.1 BHN. Consider that there was only 0.0032" difference between the two indentations and you can appreciate why the 4mm BHN numbers can be noisy.

After 4 days: 39.7 BHN / 10mm, avg 37.7 BHN / 4mm

One 4mm indentation scored 33.8 BHN while the other scored 41.7 BHN, for an average of 37.7.

After 8 days: 40.9 BHN 10mm

After 2 weeks: 42.1 BHN / 10mm

Average of all 10mm tests for the first 2 weeks: 42.1 BHN