I have a brass case .30 carbine with a headstamp of E C 4. The headstamp guide has two different listings for EC, both located in the US:
- Eau Claire Ordnance Plant, Eau Claire, WI
- Evansville Ordnance Plant (Chrysler), Evansville, OH
If wikipaedia is to be believed, it appears that Eau Claire only produced acids and powders during WWII. I couldn’t find much on Evansville, so before I decide that this was manufactured there, I thought I’d ask here.
A quick search on here only turned up info on steel case rounds but another did confirm my suspicion that the single digit 4 was indeed 1944.