See if this helps:
Western Cartridge Company formed about 1908 by Franklin W. Olin
Western Cartridge Company acquires Winchester Repeating Arms Company, December, 1931
“Division of Western Cartridge Company” begins to appear on Winchester boxes, about 1938
Olin Industries, Inc. commences in December, 1944
“Division of Olin Industries, Inc.” appears on Western and Winchester boxes, circa 1946, when civilian ammunition production begins again following WW2.
“Division of Olin-Mathieson Chemical Corp” appears in 1954
“Winchester - Western Division” of Olin-Mathieson Chemical Corp. commences about 1956.
“Division of Olin Corp.” appears circa 1969