Re: 338 wildcat help
Basically you're looking at a .340 Weatherby, a wildcat version would be an 8mm Remington Magnum necked to .338. Some neck down the .416 Remington Magnum. I believe .338 Galliard is what these are being called these days.
Going back into the fifties, if my memory is on, the .334 OKH Belted is what folks were calling it. Elmer Keith necked up and down just about every case out there to .338 I may have the lettering off.