March 10, 2024
By Allan Jones
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I’ve always gravitated to 7mm/.28-caliber cartridges, but only an old ballistician could recall those that have faded into shadow. Although they are little known today, I found them ballistically and/or historically interesting. For my references I used CIP (European) ballistic standards for dimensions and maximum average pressure (MAP) comparisons; CIP catalogs more obsolete cartridges than SAAMI.
7x33mm Sako When I first saw this diminutive bottleneck cartridge, I thought it was for a military carbine. No, it was a small-game cartridge introduced in 1942 for Sako’s short-action L42 bolt rifle. The 7x33 is based on a stretched 9mm case necked to 7mm. Sako loaded only a 78-grain FMJ or JHP bullet at about 2,400 fps. MAP is about 15 percent under the .30 Carbine, but loaded with bullets of similar weight, the cartridge would be close to .30 Carbine performance. Cartridge cases can’t be easily formed from other cases. Bertram still shows reloadable cases in its online master product list, but users say the company is not shipping them. Sako listed factory ammo until at least 2020, but it is not in the 2023 listings.
.275 Rigby John Rigby imported commercial Mauser actions to England to create his line of fine bolt-action sporting rifles. Around 1907 he created a “new” cartridge by loading lighter bullets in the 7x57mm Mauser cartridge and calling it “.275 Rigby.” The two cartridges are completely interchangeable. For some reason, the Rigby’s MAP is currently set 22 percent lower than Euro-specs for the 7mm Mauser, odd in that the Rigby was never offered in pre-1898 Mausers.
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.275 Belted Nitro Express This superb sporting cartridge is also known as the .275 H&H and .275 Magnum Rimless. Capable of close to 7mm Remington Magnum performance, it was doing that 50 years before its American cousin debuted. It is the .375 H&H case shortened to 2.50 inches and necked to hold .28-caliber bullets. A likely barrier in the United States was that wildcatters were getting the same performance with similar cartridges, such as the 7mm Mashburn Short Magnum, long thought to be the inspiration for both the Weatherby and Remington 7mm Magnums. Euro-specs for the .275 Magnum’s MAP are only 3 percent less than Remington’s version.
7x61mm Sharpe & Hart Super Developed by two Americans in 1953, the 7x61 S&H was loaded by Norma, so the standards are from CIP. Archived Hornady online handload data shows this fine cartridge can challenge 7mm Rem. Mag. performance. You either bought a Danish Schultz & Larsen rifle or commissioned a custom rifle. Norma sold ammo and reloadable cases in the U.S., but I recall when Norma distribution here was spotty in the 1960s, at least where I grew up. I found only one Dallas-area shop that usually had most Norma reloading products. The S&H also entered a U.S. market where the very good 7mm Weatherby, although still proprietary then, was already active. If you own a nice 7x61 rifle and can reload, there is little reason to replace it. CIP lists the MAP as 4,050 bar, the same as they recommend for the .30-06.
7x72Rmm This is an oddity from the early 1930s that was chambered in single-shot rifles and combo guns. Outwardly a straight-taper case, the cartridge’s CIP drawing shows a nearly imperceptible shoulder of only 2.3 degrees. The gangly case is 2.8 inches long, and the COL is 3.62 inches. Only recently did I realize the odd case design had a combo-gun advantage. Space to tuck a rifle barrel among shotgun tubes is precious. Long and lean works well. A long, skinny case allows for a bit more chamber wall thickness over the rear third of the case than do “fatter” cartridges. This is no barn burner. CIP pressure specs are 15 percent lower than for the .30-30 Winchester. Factory loads drove a 139-grain bullet at a nominal velocity of 2,440 fps, putting its performance in the same class as the .30-30.
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.280 Ross
The Ross had successes as a target cartridge but struggled in the hunting sector, likely due to bad user choices. Introduced by the Canadian Ross Rifle Co. in 1906 with a big, semirimmed case, it made 3,000 fps with a 140-grain bullet. CIP specs show the Ross uses a 0.287-inch bullet, a potential handicap for reloaders. MAP is only 75 percent of the 7mm Rem. Mag.’s Euro-specs for pressure. As happened with other breakthrough high-velocity cartridges, some hunters were using the Ross on bigger game than the fragile 140-grain bullets of the day could handle, resulting in fragmentation and poor penetration. Heavier bullets fared much better, but perceptions—right or wrong—are hard to shed. In addition, mechanical problems with early military Ross rifle actions may have left “something unwanted in the punch bowl.”
7-30 Waters This all-American round was developed on the .30-30 Win. case by Ken Waters as a flatter-shooting lever-gun cartridge. It debuted in 1984 in Winchester’s Model 94 Angle Eject rifle, which allowed normal scope mounting and sported a beefed-up receiver where the locking bolt rides. Factory ammo drove a 120-grain FNSP bullet at a nominal 2,700 fps. This cartridge absolutely delivered on its promises but still struggled. Did the public not accept the physical changes to America’s iconic lever gun that defined the AE version? Three other cartridges developed for the 94 AE (the .307, .356, and .375 Winchesters) also failed to thrive. However, I’m not pronouncing it dead. The 7-30 Waters in a 14-inch Thompson/Center Contender or similar handgun ranks among the best of the “Sub-.30” handgun hunting cartridges. The 7-30 in a Contender matches my favorite in that sub-.30 cartridge group, the 6.5 JDJ #1. Handloaded with Spitzer bullets, the Waters drives a 130-grain Speer bullet to 2,325 fps. My JDJ drives a 120-grain bullet to just under 2,400 fps—no practical difference. Why do I bring up our history? Very wise men, deeply rooted in the rich history and traditions of firearms and ammunition, always taught me that you can’t see where you are going if you don’t know where you came from.
