Savage Arms acquired Stevens Arms & Tool in 1920, and the Stevens 22-410 was the first of the Savage/Stevens O/U combination guns issued, sometime in late 1938/early 1939 as the Stevens Model 22-410.
The various Savage 24 O/U models/chamberings followed later, and none were letter-date-coded under the chambers until MUCH later (1949 to 1970).
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