7mm Musings: The 7mm Rifle Cartridges
By Chuck Hawks
The .28/7mm cartridge clan has become second in numbers only to the .30 caliber cartridges in North America. There is a wide array of 7mm contenders, from the ancient but effective 7x57 Mauser to the new 7mm WSM and 7mm Remington SAUM. Somewhere in between are the 7-30 Waters, 7mm-08 Remington, 7x64 Brenneke, .284 Winchester, .280 Remington, and the standard length 7mm Remington and 7mm Weatherby magnums. Factory loaded ammunition for all of these is available to the North American hunter.
In the extreme category are the extra long .275 H&H Mag., 7mm Dakota, 7mm STW, and 7mm Rem. Ultra Mag. These are full (.300 H&H) length magnum cartridges that require special long actions to accommodate them. The .275 H&H is obsolete, the 7mm Dakota is available only from Dakota Arms and the 7mm Ultra Mag is available only from Remington. As I write this the 7mm STW is the only member of this quartet that appears to have any viability. None of these has attained real popularity. It is unlikely that they ever will, as rifles for them are few and tend to be expensive, and they offer little or no ballistic advantage over the more common 7mm Weatherby Magnum.
Strangely, the cartridge that has most profoundly influenced the 7mm class from the 1930's to the present day has been a cartridge that is not a true 7mm at all, the .270 Winchester. The .270 uses a .277" diameter bullet, but it is so close to the true 7mm's .284" bullet that they are inevitably compared.
The best of the American standard length 7mm cartridges, the .280 Remington, was introduced as a direct competitor to the .270 Winchester. And the best of the short action 7mm's, the .284 Winchester, was introduced to provide .270 ballistics in a cartridge that would work through short action rifles.
The .270 was too well established to be overtaken by any of these 7mm cartridges. The fact that the .270 may be the best balanced long range big game cartridge ever invented probably doesn't hurt, either. In any case, none of the pretenders to the .270's throne has been very successful. The .284 is obsolete, and the .280 moribund, while the .270 is consistently in the top 5 best selling centerfire rifle cartridges, year after year. The long shadow of the .270 Winchester remains over the standard length, non-magnum 7mm class.
But there have been some very successful 7mm cartridges. The best of these has not been influenced by the .270, but rather were designed to provide a flat shooting, lower recoil alternative to the .30 caliber cartridges. The original 7x57 Mauser was the first of these, as is the newer 7mm-08 Remington. This pair of very sensible cartridges combines practical sectional density, good velocity for a reasonably flat trajectory, and good killing power with moderate recoil and excellent practical accuracy. What more could the average shooter ask for?
The 7x57 has done it all for about 100 years, but it is based on an unusual length case. Its overall length is just slightly greater than what can be accommodated by most short action rifles, so it is usually found in standard length actions, where it's performance is outclassed by longer cartridges like the .270 and .280. Mauser once built a special intermediate length action for the 7x57, but none of the major rifle makers do so today. Which eventually opened the door for its ballistic twin, the 7mm-08 Remington.
The 7mm-08 is a true short action caliber, based on the .308 Winchester case. It is the most practical and has become the best selling of all high intensity 7mm's. It makes no pretense of competing with the .270 Winchester, and so has avoided the comparisons that doomed the .280 and .284. Shooters have recognized that it is one of the best balanced short action cartridges ever designed, and it has become a legitimate all-around cartridge. The .308 and the .243, both based on the same case, still outsell the 7mm-08. But the 7mm-08 may represent a near optimum use of this case capacity for big game hunting. As I said in my article on the 7mm-08, it seems to be a cartridge whose time has come.
The 7-30 Waters relates to the .30-30 Winchester exactly as the 7mm-08 Remington relates to the .308 Winchester. It is based on a necked down .30-30 case to create a flatter shooting, lower recoil cartridge. It is an excellent deer cartridge, and deserves more recognition than it has so far received.
The 7mm Remington and Weatherby Magnums are cartridges whose time came some years ago and they have remained popular ever since. The 7mm Rem. Mag. and 7mm Wby. Mag. are attempts to wring the maximum performance attainable from a 7mm cartridge adaptable to standard length bolt action rifles. These are belted magnum cases that will work through the same rifles that accommodate .30-06 length cartridges. The big 7's provide a flat shooting, lower recoil alternative to .300 Magnum cartridges.
In performance the 7mm Magnums tread close on the heels of the .300 Magnums. Little or nothing hits harder at long range than a 7mm Magnum, and it is distinctly more pleasant to shoot than a .300 Magnum. This has endeared the Big 7's to generations of shooters, and made the Remington version the best selling of all magnum cartridges. It is adequate for all North American big game, and one of the world's finest all-around cartridges.
The 7mm WSM and 7mm Rem. SAUM are short action magnum cartridges that attempt to gain in width the powder capacity that they sacrifice in length. In other words, they are short but very fat cartridges with sharp shoulders. They nearly duplicate the ballistic performance of the popular Remington 7mm Magnum in cartridges that will function through short action rifles.
A very complete family, this 7mm clan. You can read more about these 7mm cartridges in the series of cartridge articles on the Rifle Cartridge Page.
Copyright 2002, 2015 by Chuck Hawks. All rights reserved.