WW2 .45 ammo question

[AZPhil]

Hello To all
I just got a box of 45acp that is dated 1943 and the casings are made of steel.
My question is, What year did they start making the casings in steel?

[Bob K]

I believe 1942 was the first year. The Chrysler plant in Evansville, Indiana made over 3 billion cartridges from late June 1942 to April 20, 1944.

[Johnny Peppers]

The first steel cased .45 ACP ammo was made late in 1942. In 1943 the 1¢ "penny" was also made of steel, which like the ammo had a zinc coating to prevent it from rusting.