Warren Page, during his historic tenure as Field & Stream’s shooting editor, did most of his hunting with only two rifles. One was a 7mm Mashburn Magnum (Old Betsy Number One — shown) and the other was a .375 Weatherby Magnum. The former was the brainchild of Art Mashburn, a rifle maker and wildcatter who blew out and necked down the .375 H&H case to 7mm. Warren took something over 450 head of game with it all over the world, and with only one load—the 175-grain semi-spitzer Nosler screw-machine bullet at 3,060 fps from a 22-inch barrel.
Page was good friends with Remington designer Mike Walker, and very likely sold him on the idea of building a 7mm mag of their own, which they did, and introduced in 1962. The 7mm Remington Magnum was a raging success, and killed everything everywhere. But it was not what it was cracked up to be.