The green shells were the ARROW EXPRESS high velocity shells loaded with progressive burning smokeless powders. The red shells were the ARROW "Specified Loads" which were the last gasp of the old style bulk and dense smokeless powder loads.
ARROW loads 1938.jpg
The last few ARROW specified loads appeared in the 1942 Remington Ammunition catalog. The ARROW EXPRESS 12-gauge 3-inch and 10-gauge 3 1/2 inch shells survived WW-II, last appearing in the January 1948 Remington Ammunition catalog.
The regular Remington progressive burning powder loads were called NITRO EXPRESS through the 1942 Remington Ammunition catalog, and by 1946 they were REMINGTON EXPRESS which they still are.