Another thing to note on these blue and yellow Western Cartridge Co. both Xpert and Super-X loads to help date them is the type of wads. The early boxes will show the Seal-Tite wads --
16-gauge Xpert 2 9-16 inch Seal-Tite Wads.jpg
Seal-Tite Wad.JPG
Fairly soon after WW-II Western replaced the Seal-Tite wad with their Super-Seal Cup wads --
16-gauge XPERT 2 9-16 inch Super-Seal Cup Wad.jpg
Xpert with Super-Seal Wads.jpeg
as they began using the Super-Seal "pie crimp" on their hunting loads. The 16-gauge 2 9/16 inch shells don't appear to have ever gotten the Super-Seal crimp but continued to be made with the roll-crimp to the end of production.
Just to muddy the waters, the Xpert 12-gauge Trap and 12-, 16- & 20-gauge Skeet loads got the Super-Seal crimp for 1938 and along with that the cup base wad but still the Seal-Tite wad --
Xpert Skeet & Trap Loads with Seal-Tite base wad and Super-Seal Crimp.jpg