Jon, this is what Chrysler Corp. wrote in 1946 about the .30 Carbine steel case ammunition development:
"The carbine contract was signed February 27, 1943, though long before this Evansville was converting part of its machinery. At the Advisory Board meeting in Chicago on February 18th it had been revealed that the supplementary contract for .30 carbine cartridges in steel was meeting with resistance among the using arms, where many were unconvinced that steel could be a satisfactory substitute for brass.
When Mr. Jacobson [Chrysler’s General Manager] reported this to Mr. Keller [Chrysler’s President], the latter said: "I do not know at this time what to say to you other than we should do everything Ordnance wishes us to do short of meddling in what is purely a military decision. Ordnance knows how many and what calibers and kinds of bullets the Army needs and the amounts of metals available for making them. If they ask us to make steel cases, we should do the best job possible; if they want us to make brass cases, we’ll make brass cases. The using arms know what they want; Ordnace knows what it can supply, while we know nothing of these problems and should not try to influence their professional judgement.
A month earlier, Chrysler’s president had written Mr. Jacobson: “I learned yesterday that future .45 caliber production is to be cut about a billion rounds, while future .30 carbine cartridge production is going up by about the same amount. While I understand that we have and order for the development of steel cases in the carbine ammunition, don’t be surprised if you are asked to make brass while you are developing steel. If we are going to get into the manufacture of the .30, it might be well to get started on brass and thereby have a good basis of comparision with the same product in steel.”
Though to called the turn in part, Mr. Keller could not foresee all that was coming on the carbine cartridge. Ordnance would have preferred in 1941 to have tailored a new cartridge to the new gun, but seeking too quick availability of manufacture in that critical year, it had adapted an existing self-loading cartridge to the new carbine. And though fundamentally and excellent weapon, there had not been time to sweat all the bugs out of it.
Engineering quickly whipped the metallurgical problems of the longer, tapered case, yet the cartridge would not function uniformly. They failed to feed, extract or eject surely. An Abeerden Proving Ground test of steel and brass cases fired alternately showed a trifling superiority for steel, but too many failures for both.
Baffled by variations they could not account for, Ordnance had an ultra high-speed motion picture made of the carbine in action. At 8,000 exposures a minute, the film was so deliberate that minutes seemed to pass while the hammer fell. This disclosed hitherto hidden minor flaws in the gun.
New production was corrected quickly and the carbines already issued to troops were repaired in the field, but Ordnance grew reluctant to push .30 steel cases against the prejudices of the soldier. Men who live or die by their weapons are conservative-minded about them. Steel cases were new. If a carbine jammed, the human inclination was to blame the new and strange factor. With brass again to be had, it would be easier to go on making brass cases than to convince the soldier that steel was as good."