In 1967 or so I visited Walt Kramer who lived just outside of Columbus Ohio. As I remember, he had been an Army Colonel and ran FA, or at least a part of FA during WWII. He was also a cartridge collector of US military (FA ammo). He had a small drawer full of FA produced 50/30 cartridges in a multitude of case lengths and shoulder configurations (my guess is 10-15 rounds-but it was a long time ago). He told the story that these were an Army effort to do an Anti-Tank Rifle. The rounds I looked at all had early 1940 dates.
That evening was amazing. In his basement he had two cases of FA 30-06 frangible tracers, one with the red and white tip and one with the red and cream tip.He said the difference between the white and cream color was that one used commercial powder and one military.
He also had a drawer of Gerlich 30-06 test rounds. That testing was before his time at FA, but he told the story that one Sunday as he left church someone stopped him and told him that a retired engineer had died and the wife had a bag of ammo she was wanted to get rid of. The engineer was the FA guy who had worked with Gerlich on the 30-06 tests. She was pointed out to Walt and he followed her home and picked up a full bag of the Gerlich rounds-he thought it was a full set of all the variations!
The disappointment was that he had a row of about 10 9x19mm WCC steel case cartridges that were all different case case metal finishes. They had tried copper washed finishes and different lacquer and wax treatments. Unfortunately, they had all rusted and it was impossible to tell what they had been except for the tages on some of them.
He did give me a 9x19mm Canadian blank headstamped DCCo 351 SLR which he said was the first Canadian attempt to make a blank from early in the war, and some had been sent to FA for testing. It is of course still in the collection.
Thanks to Walt, and guys like him who work in the area and save things we have examples of this stuff (I think Bill Woodin got all, or most of Walts collection).