Had some time today and looked for some Ithaca Gun Co. Magnum-Ten ads. From my limited search it doesn't seem they launched an advertising blitz for the big gun. In the July 1932, sporting magazines an ad like this appeared with the launch articles --
National Sportsman, July 1932.jpeg
National Sportsman, July 1932
From then on it seems from my limited search that Ithaca Gun Co. ran a smaller Magnum-Ten ad each August.
National Sportsman, Aug. 1933.jpeg
National Sportsman, August 1933
National Sportsman, Aug. 1934.jpeg
National Sportsman, August 1934
National Sportsman, Aug. 1935.jpeg
National Sportsman, August 1935