I did not know steel carbine cases were produced during WWII...


Box

Base

Side View

Didn't know those existed either, neat!

Chrysler

I had found some at an estate sale, thought they were unusual and was told not to be common but not entirely rare either - Gave mine to a carbine collector friend.  43 was a year for steel pennies and cartridge cases.  I still have some steel 43 dated 45acp ammo I seem to find that more often.

I wonder if there was a hierarchy of priority to switch from brass to steel - say do  Pistols and PDW cartridges  or if it was just timing of what was needed.

Brass was starting to get a concern mid war..

So they started to look at other options if needed..

Germans and Russians used a lot of steel during WW2..

I always see concerns about using wolf steel ammo in today's world... etc and its been proven already it works...

Pretty sure I have some of that loaded in some magazines. Never had a box though

I actually bought my current Plainfield commercial M1 Carbine in 2020 to run Wolf steel cased and save wear on my USGI or Fulton Armory made ones. Of course it was banned from import right after that.

IIRR the worry with Wolf is the steel is harder than the steel used by the US in WWII. That and the extractors being 70 plus years old and worn. I did replace the extractor on the Plainfield I mentioned with a NOS USGI one but never got the chance to buy any Wolf before the ban

The problem with Wolf, Tula, et al... is rarely the material, though the cases are a bit harder. The problem is the overall ammo quality.

The CMP sold Wolf 30 carbine for a while.  If it really was out of spec or severely wore out parts, I'd expect they would advise against its use rather than offer it.

The steel vs brass cased ammo debate goes on.  Brass remains prolific for a reason yet steel cased ammo has a solid reputation.

I recall in the 70s-80s lots of Garand and M14 guys would not touch a "plastic" AR15 junk rifle incapable of any accuracy.  Sometimes paradigms are just hard to get over.

Big difference between a brand new gun and however many spare parts you could possibly want, and an 80 year old rifle that has an unknown history and you're on the hook for finding good quality parts and paying for them

I have some kind of government document that states that something like 300 million rounds of .50 cal (for aircraft use) having steel cases were produced during the war.  They were heat-treated, unlike most steel cases today.

Cold-worked steel cases have an interference-fit with the chamber after firing.  They are bigger than the chamber in their free state.

Again, it's rarely the base material that is the issue; rather the quality overall coupled with the base material.

I've shot some Wolf .30 Carbine that was great and I also tore down four hundred rounds for the bullets since performance was utter crap. The Herters and Wolf 5.56 I had gave lots of issues in various rifles- a smattering of ARs and an XCR-L. The Brown Bear and Wolf 7.62x54R performed quite poorly on paper. Brass-cased from better manufacturers performed with no problems in all of those firearms aforementioned.

Eastern European steel case is rarely renowned for its phenomenal consistency. I'm sure American-made steel cased ammo would be just fine.

In a Carbine, you will get functioning issues at-worst. In something less-forgiving like an FAL or other tilting bolt that lacks primary extraction, the user is pinning a lot on the cartridge holding up its end of the bargain. Steel-cased ammo available as of recently has the reputation it deserves, which certainly isn't "solid".

Lastly, and I'm not passing judgement on the particular scenario you mentioned, but I, for one, don't concern myself much with what the CMP does or does not do. Infallible, they are far from.

P.S. I didn't mention anything about parts wearing prematurely.