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Whoa, please stop the misinformation. US contractors made lots of steel cased .30 caliber carbine cartridges during WWII.
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One of the main suppliers was the Evansville ( Indiana) Ordnance plant. Zinc plated cases totaling 500 million rounds. Also large quantities of .45 ACP ammo produced in steel casings starting around October 1942, totaling over 3.2 Billion rounds. It freed up brass for the higher pressure cartridges like .30-06 and 50 BMG.
Another steel case ammo manufacturer was Twin Cities ( Minnesota ) Ordnance plant.
Modern steel cases have slicker coatings on them, and an occasional magazine or three in a clean firearm won’t hurt. A dirty or gritty chamber is when there might be concerns with the extractor.
Three main firearms for this cartridges is the M1, Ruger Blackhawk, and various models of the AMT Automag.