Through the 1942 Remington ammunition catalog their high velocity, progressive burning powder loads were the NITRO EXPRESS and the 3 1/2 inch 10-gauge was
10NE2. By the 1946 Remington ammunition catalog their high velocity, progressive burning powder loads were the REMINGTON EXPRESS but the only 3 1/2 inch 10-gauge load offered was in their premium ARROW EXPRESS line,
AX10Mag however it was marked with an * Will not be available in 1946. By the November 3, 1948, Remington ammunition catalog the ARROW EXPRESS line was gone and the 10-gauge 3 1/2 inch Magnum shells were now REMINGTON EXPRESS with the load number
RX10Mag.
I suspect the box shown was an early stop-gap measure used until they got the red, green and cream boxes printed up.
Magnum-Ten Front.jpg
Magnum-Ten Side.jpg
Magnum-Ten Top.jpg