They probably originally came in a box that looked like this:
Attached FileI believe the jacket is Cupro-Nickel.
And now for some confusion...
30-40 Krag is/was also called .30 US or .30 Army
The cartridge for the new M1903 rifle was called .30 Government (like 45/70 was also called 45/70 Government)
So, when the M1906 cartridge was developed it was called .30 Government M1906.
BUT, in a few of it's catalogs, Winchester listed 30-40 Krag as .30 Government in the caliber offerings for the 1895 Winchester.
So, to avoid the confusion caused by Winchester, .30 Government M1903 was shortened to 30-'03 and .30 Government M1906 was shortened to 30-'06.
Winchester Staynless was their answer to Remington Kleanbore. Both companies switched to a non-mercuric, non-corrosive primer recipe, 1928 and 1926 respectively, for most of their commercial ammo offerings.