A cartridge that I think might have been really useful is a wildcat that I probably re-invented while messing around at the reloading bench one day.
I took a nickeled once-fired .38 Special case and reformed it in a 7.63 Mauser pistol resizing die, using a .38 special shell holder.
Then, using the other dies I loaded a 100 grain Speer Plinker round nose with a half jacket.
I used a light 7.63 Mauser load of Unique in it.
It Looked like it would have made a really good cartridge for a small frame Remington Rolling Block, as well as a snappy Blackhawk revolver cartridge.
A .357 magnum case would have been even better.
Anyway, having no firearm to use my new creation in, I was off to the weekend gun show, with it tucked in my watch pocket. I ran into my good friend, Tim Falconer (now deceased) who was a collector of local note in his day.
Since he had a Cartridge Collector display this time, I sat with him at his table. When he wasn't looking I placed my wildcat at the end of a row of cartridges that were standing on the table.
Later, I asked him about those cartridges and he rattled off their history until he came to mine, whereupon he said something like "What the fork?"
He liked it so I gave it to him.
Fun times.
