That is an absolutely beautiful Eley box.
I have never seen one before.
The .40-60 Colt was also known as the .40-65 Winchester. Colt chambered it in their large frame Colt Lightning pump action repeating rifle.
The .40-65 WCF cartridge was introduced in 1887 for the 1876 Winchester rifle. Marlin adopted the cartridge for their Model 1895 rifle in 1895. The .40-65 WCF made the transition from the black powder era to smokeless high velocity loads in the early 1900’s.
Cartridges were loaded by Winchester, Remington - UMC and Peters. UMC also loaded wooden saboted shot cartridges.
Frank Barnes states that the .40-60 Colt has a slight neck. Any sample I have seen has no neck. It is dimensionally the same as the .40-65 Winchester and .40-60 Marlin. The .40-60 Colt appears on a Winchester cartridge board but is not listed in any of their catalogs. UMC seems to be the only manufacturer listing the cartridge.
British manufactured cartridges were preferred and given special preference in the British Commonwealth and possessions which is one reason Eley manufactured traditionally “American” cartridges.
Others will be able to add more or correct any of my mistakes.
Could you post a image of the cartridge and the head stamp please?
Thanks for showing such an interesting box.
All the best,