I have an EC round from 1942 that has the usual steel case but the bullet does not react to a magnet, so I assume its copper clad lead.
I have a partial box from 1943 that is also steel cases but the bullets are definitely steel too, copper clad I assume.
What was the purpose of going to a copper clad steel core? Did this last until the war’s end? Did others load steel core 45s? (Enlighten me John!)