Maybe you’ve heard me complain about the 7mm Rem Mag before. I have been complaining about it for some decades now, and whenever I do, the legions of 7mm Rem Mag fans fart and sputter, wondering what there is not to like. For their sake, I’ll concede that the cartridge has been very successful and has been used to flatten an untold number of critters. But, when you go to the trouble of buying a rifle chambered for magnum cartridge and you plunk down your money for ammo to feed it, the “magnum” in question ought to be a real magnum. Not the weak-kneed and flaccid excuse for a magnum that is the 7mm Rem Mag.

7mm Rem Mag: Real or Not Real?

You may recall the scene from the movie Crocodile Dundee where a mugger threatens Mick Dundee with a switchblade. “He’s got a knife,” says Dundee’s companion and recommend he hand over his wallet. Dundee smiles, draws a blade the size of a small machete, and says, in the ghastly accents that are accepted as English in the Land Down Under, “’At’s not a knoife. ‘At’s a knoife.”

Or let’s apply the same principle to sports cars. In the mid-1960s, the race-car designer Carroll Shelby sold a sports car called the Cobra with an English AC body and a small-block 287 Ford V-8. It was very cool and went fast. Then Shelby came to his senses, reinforced the AC frame, and installed the 427 big-block Ford V-8. The Cobra was now more of a projectile than a car. Original 427 Cobras today can sell for upward of $4,000,000. The 289s do not.

So it is in designing magnum cartridges: Anything worth doing is worth doing to excess. You can call any round you want a magnum but that does not make it one. A genuine magnum has to develop a lot more velocity than a standard cartridge to claim the title. And thus lies the problem with the 7mm Rem Mag, which has the name but not the horsepower.

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Why Is the 7mm Rem Mag Underpowered?

Warren Page, who was the first gun writer to get behind 7mm magnums, did his hunting with a great big cartridge called the 7mm Mashburn Magnum. Page figured the best bullet for it was the 175-grain Nosler Partition, and the Mashburn held enough powder to send that slug out of its 22-inch (yes, 22-inch) barrel at 3,050 chronographed fps.

But when it came time (1962) for Remington to get in the 7 mag business, designer Mike Walker came up with a much smaller case than the Mashburn. It propelled a 175-grain slug at 2,800 fps, or a bit more, from a 24-inch barrel. So, why the 7mm Rem Mag’s cut in power?

My guess is price and recoil. A big case would jack up the price, and the fact that a Mashburn-capacity cartridge would burn almost 40 percent more powder would give the recoil and muzzle blast a major boost, neither of which would help sales. Walker was right. The cartridge he fathered was an immediate hit, largely because it kicked very little for a “magnum.” And thus it has been ever since. Trusting souls who swear by the 7mm Rem Mag are seduced by the larger-than-standard case, and because it kicks very little compared to a real magnum they shoot it well, and the animals go down, and everyone is happy except the animals.

The Other Real 7mm Magnum

But some shooters were not fooled. In 1978, Remington came out with its 8mm Magnum, which was as popular as a colonoscopy, and gun writer Layne Simpson, who worked for Shooting Times magazine, beheld the 8mm’s massive case and realized that if you necked it down to 7mm, and could lay hands on a genuinely slow-burning powder, you would have a real 7mm Magnum. So Layne, who is a very bright guy and is trained as an engineer, did the smart thing and waited until several ultra-slow powders came on the market, and created the 7mm Shooting Times Westerner, or 7mm STW as its friends call it.

photo of 7mm RUM compared to 7mm Rem Mag
If you want a real 7mm magnum, the RUM is certainly one. Nosler

The STW dwarfs the 7mm Rem Mag, and it will send a 175-grain bullet out of a 26-inch barrel (which you gotta have) at 3,200 fps, or very, very close. It electrified the shooting world, and was recognized by SAAMI in 1996. I recall a plane ride from Gillette, Wyoming, to Denver during which I sat behind a guy who had killed an antelope with a single very long shot from an STW, and he ranted as though he had just been through a religious experience which, in fact, may have been the case.

But fate was not kind to the STW. In 2001, Remington effectively killed off the STW by introducing the 7mm Remington Ultra Mag. The RUM’s performance was the same as the older cartridge almost to the foot per second. But the point has been made. There are at least two genuine 7mm magnums out there. But the original, 1962 version ain’t one of them.

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