The Saga of the 7mm Caliber
September 21, 2005
Once considered an exotic European, 7mm has become a favorite domestic caliber.
I'm sure that in 1892 when Peter Paul Mauser was putting the finishing touches on a 7mm cartridge he had just designed, little did he know he was launching what would prove to be the most popular game caliber in the history of smokeless powder.
Here in the states the 7mm bore will in all probability remain a distant second in popularity to the .30 caliber, but when you consider the advantages the .30 has had, it's pretty impressive how popular the 7mm has become in such a relatively short span of time. After all, the .30 was the official caliber of the U.S. military from 1892 to 1967, first in the form of the .30-40 Krag, followed by the .30-06 and then the .308 Win. (7.62 NATO). Then there's the little matter of there being some 10 million Winchester Model 94 and Marlin lever-action rifles chambered in .30 WCF. It's no wonder, then, that no matter how you track it--through sales of loading dies, component bullets, loaded ammunition or unprimed brass--.30 will always come up number one simply because there are so many of them out there. New-gun sales figures, however, are something else again, for the 7mm competes quite successfully with the .30 in that category.
Anyway, the 7mm as a smokeless-powder caliber was launched when Spain adopted the 7mm Mauser as its martial cartridge in 1893, first in a limited number of Mauser's Model of 1892, then in serious quantities in the Model '93. The cartridge is known by at least four names: Spanish Mauser, 7mm Mauser, 7x57 and in England as the .275 Rigby. It was eventually adopted by the armies of Mexico, Brazil, Chile, Uruguay, Colombia, Venezuela, Costa Rica, Serbia, China, Persia, Transvaal and the Orange Free State.
The first American company to chamber for the 7mm Mauser was Remington in its Model 1897 Rolling Block Military Carbine, the entire production of which went to the Mexican government. The following year, though, the chambering was offered in the No. 5 Sporting & Target Rifle version of the Rolling Block, along with the .30-30 Win. and .30-40 Krag. That same year the 7mm chambering was also added to the five-shot Remington-Lee bolt action rifle. In either case, relatively few 7mm Mauser rifles found themselves in the hands of America's hunters and shooters.
The story here stayed pretty much the same through the 1920s, '30s and '40s--Remington only offered the 7mm in its '17 Enfield-based Model 30 bolt-action rifle and Winchester in its Model 54 (and later in the Model 70). All together, though, it was a mere drop in the bucket; few other than handloading rifle cranks were even aware of the 7mm's existence.
The only other 7mm cartridges that had any presence whatsoever on these shores were the 7x64 Brenneke and the 7x61 Sharpe & Hart, for which Norma of Sweden was the main source of ammunition--also, the 7mm Weatherby Magnum, which goes back to the mid-'40s. But again, we're talking a tiny percentage of avante garde hunters handloading for custom-built rifles. As a caliber, the 7mm was still wallowing in obscurity as late as the 1950s.
That all started to change, however, in 1957 when Remington introduced its .280, the first commercial 7mm (.284) cartridge from a major American arms company. The .280's sole raison d'etre was to compete with the phenomenally popular .270 Win. With the 20/20 hindsight that time bestows, it can be said that Remington made a mistake by developing the .280 for use in the semiauto Model 740 because it had to be loaded to pressures levels below those used for the .270 Win., which was designed strictly for bolt guns. Once that decision had been made and there were rifles and ammo in the hands of consumers, there was no turning back.
Even though Remington quickly decided to add the .280 to the list of chamberings offered in its Model 721 bolt action, it couldn't hop-up the factory loads to match the .270 because of the 740s out there. Word spread quickly--thanks to the emerging gun magazines of the day--that the .280 wasn't quite a match for the .270.
Bottom line: The debut of the first commercial 7mm cartridge in the American marketplace was less than auspicious. Remington, however, was convinced the 7mm had a future here, so just five years later, in 1962, the company introduced its 7mm Rem Mag in conjunction with its equally new Model 700. I believe the company took a calculated risk by using the metric designation because historically, metrics had been looked upon as being, well, foreign, and no cartridge with an "mm" suffix had ever achieved popularity here.
Talk about exceptions to the rule! The 7mm Rem Mag in the sexy new Model 700 rifle was successful beyond Remington's wildest dreams. Suddenly, with the 7mm Mag, the .28 caliber was now firmly planted on American soil, and over the next 40 years Remington above all others would nurture it.
First to respond to Remington's Big Seven was Winchester with its .284 Win., a short-action cartridge whose rationale was pretty much the same as that espoused for the .280 Rem six years before--namely, to provide .270-like performance in the Winchester Model 88 lever actions and Model 100 semiautos. And it was a failure for pretty much the same reasons as the .280: It didn't quite match .270 Win. ballistics in factory loadings.
Hoping to capitalize on the success of its 7mm Mag, Remington tried to breathe new life into the languishing .280 in 1979 by formulating a higher-performance load (but still within the same pressure parameters that would allow its use in the 742/740/7400-series rifles) and renaming it 7mm Express Rem. That didn't work very well either, and within a couple of years its name was changed back to .280 Rem.
Just one year after announcing the 7mm Express, the Remington people came up with yet another .28-caliber cartridge to bear its headstamp, the 7mm-08, a cartridge derived by simply necking down the .308 Win. By then the round had achieved some prominence as a wildcat among silhouette shooters. Performance-wise it was very close to what handloaders could get out of a 7mm Mauser in a modern bolt action.
So now Remington had three players in the 7mm game: one of 7x57 case capacity, one of .30-06 capacity and one of standard-length belted-magnum capacity. There was only one direction for it to go, and that was bigger. So bigger it was with the 7mm STW (Shooting Times Westerner), a wildcat developed by my friend and colleague Layne Simpson and legitimized by Remington in 1997. The STW is simply the 8mm Rem Mag necked down to 7mm; as such, it's based on a full-length .375 H&H case "improved" to maximize case capacity.
In the same vein as the STW, the 7-30 Waters, a wildcat developed in the late '70s by Ken Waters to extend the range of lever actions like the Winchester 94 and Marlin 336, is loaded commercially by Federal, PMC and Winchester. With U.S. Repeating Arms chambering for it, that makes it a viable commercial round that we can add to the list of factory-loaded 7mms.
In the mid-'90s three proprietary 7mm cartridges appeared on the scene, one courtesy of Dakota Arms and two from Lazzeroni (one based on John's huge Rigby-size case, the other on a shortened version thereof to fit the 2.8-inch magazine of his and short actions). The latter, known as the 7.21 Tomahawk (but still a true 7mm of .284 diameter), was the first of the true "short magnums."
The rest of the story I'm sure you know--Winchester's 7mm Short Magnum, Remington's 7mm Ultra Mag and 7mm Short Action Ultra Mag, all introduced within the last three years. All told, there are currently 14 cartridges of 7mm caliber being loaded among the major ammo manufacturers--Federal, Hornady, Norma, PMC, Remington, Winchester and Weatherby.
So to what do we owe this relatively sudden turn of rags to riches for the 7mm bore size? There is, of course, no simple answer, but if there were, I believe it would be primarily attributable to the fact that today's hunters and shooters, typically those who read magazines like RifleShooter on a regular basis, are a lot more knowledgeable than a generation or two ago, plus the fact that there's a lot more of them.
Let's face it, anyone who opts for a 7mm, whether it's the 7mm-08 or the 7mm Ultra Mag, is looking for high energy retention and flat trajectories, which means a .270 or a .30 of some sort would be the only logical alternatives for consideration. There is nothing inherently superior about a bullet that measures .284. Anything a 7mm can do, a .30 caliber of comparable sectional density and ballistic coefficient can also do. The catch is, in order to send a .30-caliber slug over a trajectory as flat as that 7mm bullet, about 20 percent more recoil is going to be generated.
There's no question that whatever the terminal range--200, 300, 400 or more yards--the .30 is going to arrive with more energy. The question is how much you need. A 7mm Rem Mag, for example, pushing a 150-grain Barnes XBT at 3,100 fps, arrives at 400 yards with nearly 2,100 ft-lbs of energy; that exceeds the 2,000 ft-lbs of delivered energy they say is required to make a good elk cartridge. Pushing a .30/180 Barnes XBT, which has comparable SD and BC ratings, at the same 3,100 fps from a .300 Win Mag would have it arching a slightly less flat trajectory and arriving with about 250 ft-lbs more energy. How important is that, particularly when you consider that in an 8.75-pound rifle, the 7mm is going to belt you with 22.8 ft-lbs of recoil, compared to the 28.5 the .300 delivers? That's 20 percent more recoil for a less flat trajectory and 15 percent more energy.
Another way of looking at it is that, based on similar recoil levels, you can be shooting either a .308 Win. or a .280 Rem, a .30-06 or 7mm Rem Mag, a .300 Win. Mag or a 7mm STW. In all three cases the 7mm produces clearly superior downrange performance in terms of delivered energy and trajectory at any given recoil level. You could say you get more buck for the bang.