Unknown .45 bottleneck

The cartridge pictured here has been referred to as the .45 Ernest in several of the Buttweiler auction catalogs (see Vol X, No 3, lot 335), and as the .45-1.452" by George Hoyem in his Vol 4 of The History & Development of Small Arms Ammunition. It has also been referred to in the past as possibly being a .56-46 Spencer center fire. The case is the Berdan primed, folded head style of UMC. Does anyone know if there has been a positive identification of this cartridge? The dimensions are as follows:

bullet - .458"
neck - .487"
head - .562"
Rim - .676"
case length - 1.441"