The box of Remington 28 gauge shells referenced earlier also has a similar warning on the back of the box "CAUTION" "Do not expose shells loaded with smokeless powder to artificial heat as the moisture content of the powder will be greatly reduced and its strength greatly impaired". This print is so tiny that my old eyes can hardly read the inscription; but there is nothing on the box regarding extreme cold.
I forgot that I do have one original two-piece box by Winchester; a box of 410 shells marked "2 1/2 inch 7 1/2 Ch R106 71/2C". The box label is black with red border striping; and features a big red "W" above what appears to be a green shell. Shells inside box are a faded light brown color, roll-crimped, and their loaded length is 2 3/8". There is no Damascus/Twist steel warning on this box; but this inscription is on the bottom:
"CAUTION" "Do not expose these shells to extremes of heat or moisture. Shells loaded with smokeless powder will withstand ordinary climactic changes but will vary in strength if exposed to abnormal conditions". I have no idea as to the age of this ammo; but on the box are these dates "Patented June 9 - 30, Dec. 9, 1896, July ?, 1900, July 14, 1903"
