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.
Page’s Mashburn used 75 grains of the old Hodgdon 4831, which was a very hefty charge of powder. However, the Remington Magnum was a much smaller cartridge and delivered far less velocity. It did so well because it was a very effective cartridge but because very few shooters at the time had chronographs. People heard the word “magnum” and were convinced they were getting a big dose of extra power even if they weren’t
I’ve done considerable hunting with, shooting, and chronographing of the 7mm Remington Magnum, and with the 160-grain bullet, which is the best all around weight, you can get around 2,950 fps from a 24-inch barrel. This is a formidable load, but consider that with the same length barrel, you can get that same velocity from a standard .270 shooting 150-grain bullets. The truth is that you can hunt from now until the sun goes supernova and not see any difference in effectiveness between the two cartridges. What you will notice, however, is that the 7mm mag kicks more and makes more noise.
The one real advantage of the 7mm Remington Magnum is that it will shoot 175-grain bullets, but at the real world velocity of 2,850 fps, not the 3,060 that Lefty Page was getting.
I’m not knocking the 7mm Remington Magnum; it’s a highly effective cartridge. But if a magnum round is supposed to give loads of extra velocity, then it ain’t much. That honor belongs to Remington’s collarbone-cracking 7mm Ultra Mag and middle-ear-mangling 7mm STW. Both of them burn lots and lots of powder and deliver great gobs of velocity, and if that’s what you’re after, they will deliver in spades.