Do we cast our boolits in molds or moulds? I have seen both spellings and can’t remember, if I ever knew, what was correct. It’s not an easy question.
Some dictionaries say we cast we cast in moulds and find mold on old bread. Others say both are correct. Lee Precision uses “mold” and Lyman uses “mould”
Here’s an explanation I found.
https://writingexplained.org/mold-vs-mould-difference
Hope this will be of interest to someone.