The 6.5mm Cartridge Family
By Chuck Hawks
6.5mm cartridges are popular in Europe and European shooters have several 6.5mm cartridges that are virtually unknown in North America. Despite the fact that no 6.5mm/.264 cartridge has ever become a best seller in North America, probably because of our long love affair with the .270 Winchester, we in the New World have a good selection of such cartridges from which to choose. Some are imports and some were designed in the US.
In recent years, the popularity of the 6.5mm caliber has increased and new 6.5mm cartridges have been introduced by American rifle and ammunition companies. I like to think this is at least partly due to the influence of Guns and Shooting Online. We have published numerous favorable articles about the caliber and I am, perhaps, identified with the 6.5mm bore as much as any contemporary gun writer.
According to the various reference books on my desk, factory loaded 6.5mm cartridges available in North America include (in roughly increasing order of power) the 6.5mm Grendel, 6.5x50mm Jap., 6.5x52mm Carcano, 6.5x54mm Mannlicher-Schoenauer, 6.5x55mm SE, 6.5mm Creedmoor, .260 Remington, 6.5-284 Norma, 6.5mm-06 A-Square, 6.5mm Remington Magnum, .264 Winchester Magnum, .26 Nosler and 6.5-300 Weatherby Magnum. An idea of the international acceptance of 6.5mm caliber rifles can be gleaned from the places the cartridges named above originated. These include Austria, Italy, Japan, Sweden and the United States. Even though some of these numbers date from the end of the 19th Century, they are all modern looking, rimless designs that are suitable for use in modern hunting rifles.
Something of an anomaly is the 6.5mm Grendel, which was designed specifically for the AR-15 platform. This restricted the cartridge's overall length (2.26" COL), maximum average pressure (45,000 psi) and neck length (0.243"), with the result that it is factory loaded only with 90-123 grain bullets. (Reloaders can use bullets as heavy as the 129 grain Hornady at MV's up to 2350 fps.) For example, the Hornady Custom factory load with a 123 grain SST bullet has a muzzle velocity (MV) of 2590 fps, making the 6.5mm Grendel best suited for the smaller species of Class 2 game. Nevertheless, the 6.5mm Grendel is one of the most effective of all AR-15 platform hunting cartridges.
The 6.5mm Creedmoor was designed by Hornady as a long range target cartridge for autoloading rifles with 28" barrels. In that format, its performance is essentially equal to the .260 Remington, launching a 140 grain A-Max bullet at a MV of 2820 fps. Chambered in sporting rifles with typical 22" to 24" barrels, its ballistics suffer considerably. The Creedmoor is based on a shortened .308 Winchester case with a very sharp shoulder and loaded to the same 52,000 cup MAP as the .308. Since it is based on a shorter case with less capacity, as a hunting cartridge, it can never quite equal the performance of the .260 Remington and 6.5x55 SE, if all three cartridges are loaded to the same maximum average pressure (MAP).
European hunters have always favored 6.5mm cartridges and European factory loaded 6.5mm cartridges include the 6.5x54mm M-S, 6.5x55mm SE, 6.5x57mm Mauser, 6.5x58R, 6.5x61mm Mauser, 6.5x65mm RWS and 6.5x68mm RWS (Schluer). In addition, there are rimmed (R) versions of the 6.5x57, 6.5x61, 6.5x65 and 6.5x68 intended for use in single shot rifles, double rifles and combination guns (drillings). There are also several obsolete or obscure European cartridges that are beyond the purview of this article.
6.5mm bullets are generally available in weights ranging from about 90-160 grains, suitable for shooting everything from varmints to Scandinavian moose. For most big game hunting, the 6.5mm cartridges are probably at their best with 140 grain bullets.
Although relatively small in bore diameter, the 140 grain .264" bullet (SD .287) is a full hunting weight projectile that offers excellent sectional density (SD) for unusually deep penetration and a high ballistic coefficient. It is a very hard bullet to beat and few bullets designed for hunting thin-skinned (Class 2 and Class 3) game in any caliber are its equal.
The 6.5x50, 6.5x52 and 6.5x54 (with appropriate bullets) make particularly soft shooting Class 2 game cartridges that practically anyone can learn to shoot well. For shooters on a budget, all three are available in relatively inexpensive military surplus rifles. In addition, the 6.5x54mm was a popular chambering in the famous Mannlicher-Schoenauer sporting rifles ("The World's Finest Rifle").
These cartridges generally launch a 140 grain bullet at a muzzle velocity (MV) between 2200-2400 fps. Because they can handle full hunting weight bullets that will easily penetrate to the vitals of any Class 2 game animal, they are far more deadly than their modest paper ballistics might suggest. The 6.5x54, in particular, has been used to harvest practically every game animal in the world, including African elephants!
The mid-capacity 6.5mm hunting cartridges include the 6.5mm Creedmoor (mentioned above), .260 Remington, 6.5x55 and 6.5x57, in increasing order of case capacity. The 6.5x55 is based on a unique case, while the 6.5x57 is based on a necked-down 7x57mm Mauser case and the .260 Remington is based on a necked-down .308 Winchester case. Both Remington and A-Square applied for SAAMI standardization of the wildcat 6.5mm-08, but it was Remington's application that was accepted, as the .260 Remington.
The best known and most popular of all 6.5mm cartridges is undoubtedly the 6.5x55mm. Introduced in 1896 for use by the armies of Norway and Sweden, its case capacity is just about optimum for a 6.5mm cartridge and it was quickly accepted as a big game hunting cartridge. The 6.5x55 has been used to harvest more Scandinavian moose than any other caliber. It has been offered in many fine hunting rifles and is often seen in the U.S. in surplus Swedish Mauser Model 1896 military rifles at bargain prices.
These are moderate recoil big game cartridges ideal for all Class 2 game and they can be used to harvest Class 3 animals in the hands of a careful shooter. They can launch 140 grain hunting bullets at MV's around 2700 fps from a 24 inch barrel. The 6.5mm Creedmoor, 6.5x55 and .260 are also popular for use in target rifles, so their potential accuracy is unquestioned.
At present, the highest performance, short action, 6.5mm cartridges are the 6.5mm-284 and 6.5mm Rem. Magnum. The 6.5-284 is based on a necked-down .284 Winchester case and the 6.5mm Rem. Mag. is based on a shortened and necked-down 7mm Remington Magnum case.
As factory loaded by Nosler, the 6.5-284 launches a 125 grain bullet at a MV of 3000 fps and the 6.5mm Rem. Mag. launches the same bullet at 3025 fps. With 140-142 grain bullets, Nosler reloading data shows maximum MVs of 2900-2950 fps for the 6.5-284 and 3000-3050 fps for the 6.5mm Rem. Mag.
The standard (.30-06) length cartridges are the 6.5x61mm, 6.5mm-06, 6.5x65mm, 6.5x68mm and .264 Win. Mag. They are capable of driving a 140 grain bullet at around 2900-3030 fps MV from a 24 inch barrel. With appropriate bullets, these are fine long range big game cartridges.
The .264 Win. Mag. was introduced in 1958 and it remains among the premier long range hunting cartridges. Current Winchester and Remington factory loads drive a 140 grain spitzer bullet at a MV of 3030 fps from a 24" barrel. Reloaders can duplicate .270 Magnum velocities (about 3100 fps) with 140 grain bullets when fired from 26" barrels. The .264 Win. Mag. has been offered by several rifle makers over the years, with the Winchester Model 70 being its most common and enduring home.
The .264 was introduced in a special Model 70 rifle with a 26 inch barrel named the "Westerner" that was specifically intended for long range antelope, mule deer and elk hunting. The original factory load ballistics called for a 140 grain bullet at a MV of 3200 fps. A 26 inch barrel is still a good idea for those who wish to extract the maximum performance from this cartridge. Recoil and muzzle blast are sharp.
At the top of the 6.5mm performance spectrum are the .26 Nosler and the 6.5-300 Weatherby Magnum. They are recent designs, the .26 Nosler in 2013 and the 6.5-300 Wby. in 2017. For bullets of a given sectional density, these are among the flattest-shooting big game hunitng cartridges in the world. Both cartridges burn a lot of powder, are seriously over-bore, and barrel life can expected to be short. Recoil is right up there with other big magnum cartridges shooting bullets of similar weight.
The .26 Nosler is based on a shortened Remington Ultra Mag case and is designed to work in standard length rifle actions. .26 Nosler factory loads launch a 140 grain bullet at a MV of 3300 fps from a 24 inch test barrel.
The 6.5-300 is based on a necked-down, full length, .300 Weatherby Magnum case. It requires a rifle with a long Magnum action, such as the Weatherby Mark V. 6.5-300 Weatherby factory loads claim a MV of 3395 fps from a 26 inch test barrel.
Practically anyone who is not prejudiced against small bore rifle cartridges can find happiness with one or another of these 6.5mm cartridges. All are available from at least one major ammunition manufacturer in the U.S. or Europe and several are also available from specialty ammunition companies.
NOTE: All of these 6.5mm rifle cartridges are covered in detail in individual articles on the Rifle Cartridges page. Some are included in rifle comparison articles.
Copyright 2009, 2017 by Chuck Hawks. All rights reserved.