HackerThe world depends on a collection of strange items. They're not cheap
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Caption notes
Peanut butter and a bullet with manufactured marks do the same job in this visit to NIST. Each gives a lab a reference whose properties have already been characterized and whose material resembles the sample under test.
Archived captions (transcription method unspecified) ↗Original passages · 2
you would want to use the closest standard reference materialThey weren't fired through a gun, they were manufactured.