6.5mm Wildcat

A recent acquisition of a double rifle (made by Georg Honold, Ulm) That was originally chambered for 6.5x 58R Sauer. In 1950 it was re-chambered to a wildcat based on the 30-40 case. It is labeled on the old boxes of re-formed 30-40 brass, “6.5 G.E.K.” and one box labeled 6.5/30-40. The cartridge was supposedly the work of an Edward Nickerson of Buffalo, NY. He also did the re-chambering. Has anyone heard of this wildcat before? It is a pretty straight forward loading and forming procedure and it has a set of dies made by Nickerson. Hoping someone here might have some knowledge of Mr. Nickerson and his cartridge and what the G.E.K. stood for, probably initials, but, who’s?
case length= 2.26", 57.5mm
rim dia =.537" ,13.65mm
Base dia. =.457" , 11.61mm
Shoulder dia.= .441", 11.20mm
base to Shoulder 1.839", 46.7mm
base to neck =1.963", 49.87mm
neck dia. =.296", 7.54mm
dimensions from a fired unsized case.