Compared: The 6.5x55 SE and 7x57 Mauser
By Chuck Hawks
In Europe, where they originated, these two cartridges are very well known, and many Australian, African, North and South American hunters also use rifles chambered for the 6.5x55 and 7x57. Since I have lived in the U.S.A. my entire life, this article will unavoidably have a North American perspective, but I trust it will still be of interest to hunters and shooters from other lands.
Since I have also written an article comparing the .260 Remington and 7mm-08 Remington, much of the material in this article will be essentially identical. The .260 is just a newer version of the 6.5x55 based on the .308 Winchester case, and the 7mm-08 is a newer version of the 7x57, also based on the .308 case.
The 6.5x55 SE
The 6.5x55 was adopted as the service cartridge of Sweden and Norway in 1894. It subsequently become a very popular sporting cartridge in Scandinavia, and eventually caught on in the rest of the world, including North America. In the U.S. it is known as the "6.5x55mm Swedish Mauser" or just the "6.5mm Swede." The 6.5x55 is one of those fortunate few cartridges that is exceptionally well balanced. Like all 6.5mm cartridges, its biggest advantage is the high sectional density (SD) of its bullets.
Despite its age, the 6.5x55 is a modern looking rimless cartridge with a sharp 25 degree shoulder angle and the case and neck length to allow it to efficiently handle long, heavy bullets. That is its main advantage over its newer ballistic twin the .260 Remington.
Most ammunition manufacturers load for the 6.5x55. Typical U.S. factory loads for the 6.5x55 drive a 139-140 grain bullet at a muzzle velocity (MV) of 2550-2600 fps. Higher performance Light Magnum loads from Hornady advertise a 129 grain bullet at a MV of 2770 fps and a 139 grain bullet at a MV of 2740 fps.
Norma of Sweden offers a 139 grain bullet at a MV of 2854 fps, a 140 grain bullet at a MV of 2789 fps, and several different 156 grain bullets at MV's ranging from 2526 fps to 2644 fps. RWS of Germany offers several 6.5x55 loads including a 127 grain bullet at a MV of 2850 fps and a 154 grain bullet at a MV of 2670 fps. Sellier & Bellot of the Czech Republic loads a 140 grain PSP bullet at a MV of 2645 fps. These are typical of European 6.5x55 loads, which on average are loaded to higher pressure than U.S. factory loads.
Reloaders with old military rifles can safely achieve velocities similar to the standard U.S. factory loads. In the U.S. the maximum average pressure (MAP) for the 6.5x55 is held to only 46,000 psi, but reloads for modern rifles such as the Ruger M77 and Winchester Model 70 can safely be taken to 50,000 cup. This allows reloaders with modern rifles to equal and sometimes exceed the European factory loads.
In the U.S., Dakota, Ruger and Winchester chamber their rifles for the 6.5x55. In addition Blaser, CZ, Howa, Sako, Sauer, and Tikka offer 6.5x55 rifles for sale in the U.S. market. These and other makes are available in Europe.
The 7x57 Mauser
The 7x57 Mauser cartridge was introduced in 1892 as a military cartridge, and it quickly became popular as a sporting cartridge. It is widely used in Europe and Africa as an all-around cartridge, and it also has a considerable following in the rest of the world. In America the 7x57 is commonly called the "7mm Mauser," and the British call it the ".275 Rigby."
The 7x57 is the rimless cartridge that basically set the standards to which most high intensity cartridges are designed to this day. It pioneered the now standard rim diameter of .473" and rim thickness of .049". These are the same dimensions used by the 8x57, .30-06, .308 and all other modern standard cartridges. The 7x57 has a 20 degree shoulder angle and the case and neck length to allow it to efficiently handle long, heavy bullets. That is its main advantage over the newer but ballistically similar 7mm-08 Remington.
Standard U.S. factory loads drive a 139-140 grain bullet at a muzzle velocity of 2660-2700 fps and a 175 grain bullet at a MV of 2440 fps. Hornady offers 7x57 loads in their Light Magnum line that drive a 139 grain boat-tail bullet at a MV of 2830 fps and a 139 grain Spire Point flat base bullet at a MV of 2950 fps.
European loads are similar or, in some cases, slightly hotter. Norma offers a 150 grain bullet at a MV of 2690 fps. RWS offers a 123 grain bullet at a MV of 2955 fps, a 139 grain bullet at a MV of 2625 fps, a 154 grain bullet at a MV of 2690 fps, and a 177 grain bullet at a MV of 2460 fps. Like the 6.5x55, the SAAMI MAP for the 7x57 is 46,000 cup, but reloads for strong, modern rifles can safely be loaded to 50,000 cup.
In the U.S. Dakota, New Ultra Light Arms, and Ruger chamber their rifles for the 7x57. In addition Blaser, CZ, EAA, and Tikka offer 7x57 rifles for sale in the U.S. market. These and other makes are available in Europe and elsewhere.
Both the 6.5x55 and 7x57 are covered in detail in articles on the Rifle Cartridge Page. They are at their best with bullets weighing between 120 and 160 grains, although other weights are available. The 6.5x55 uses standard .264" diameter bullets. The 7x57 uses standard .284" diameter bullets.
There are meaningful differences between .264" and .284" bullets. That .020" difference in diameter shows in bullet frontal area and sectional density. Both are important in evaluating killing power. The bullet's velocity, energy, and trajectory should also be considered, which further complicates matters.
Comparing bullets of the same weight (let's use 140 grain Nosler Partition bullets as an example) favors the 6.5x55 in sectional density (.287 vs. .248) and theoretically wound channel depth, and favors the 7x57 in bullet frontal area and theoretically wound channel diameter. That is, of course, assuming that all other factors are equal. But all other factors are seldom equal. According to the fifth edition of the Nosler Reloading Guide, the 7x57 can launch a 140 grain bullet about 100 fps faster than the 6.5x55 with maximum loads (2892 fps vs. 2790 fps).
If bullets of equal sectional density and design (this time let's use 120 grain 6.5mm and 140 grain 7mm Nosler Ballistic Tip bullets as examples) are compared at the same impact velocity, the penetration should be equal. Unfortunately, in the real world, things are not always equal. According to the Nosler Reloading Guide, near maximum pressure loads in the 6.5x55 will drive the 120 grain .264" bullet (SD .246) at about 3000 fps and similar pressure loads in the 7x57 will drive the 140 grain .284" bullet (SD .248) at about 2900 fps.
One conclusion seems inescapable from all of this. In the examples above, neither cartridge seems to have a significant advantage in trajectory. They have very similar long range trajectories when loaded to the same pressure with bullets suitable for big game hunting. Since there is no significant difference in trajectory we are going to have to look elsewhere to find meaningful differences between the two cartridges.
The 7x57 has a modest advantage in muzzle energy with full power loads. An examination of factory ballistics tables shows this to vary between approximately 100 and 200 ft. lbs., depending on bullet weight and the individual load. How much of that extra energy it retains at long range depends on the relative weight and BC of the bullets chosen for the two cartridges. It seems to vary between about 0 and 100 ft. lbs. at 400 yards.
For what it's worth, the "Optimal Game Weight (OGW)" figures from Edward A. Matunas and published in the Lyman 47th Reloading Handbook shows that, for the most favorable factory loads, the OGW for the 156 grain 6.5x55 bullet at the muzzle is 679 pounds. For a 175 grain 7x57 bullet the OGW for the 175 grain 7x57 bullet at the muzzle is 667 pounds, which indicates equal killing power. The OGW numbers remain that close all the way out to 400 yards, the longest range quoted in the table.
To summarize the recoil situation, in rifles of the same weight the 6.5x55 kicks less that the 7x57 with bullets of the same sectional density loaded to similar velocity because the 6.5 mm bullets are about 20 grains lighter. With bullets of the same weight loaded to similar velocity, the recoil of the 6.5x55 and 7x57 are essentially equal.
For reloaders, bullet selection and availability is important. Almost every bullet maker offers a good selection of both 6.5mm (.264") and 7mm (.284") bullets for every application for which either cartridge is suited. There are actually more choices in 7mm, but the selection in 6.5mm is entirely sufficient. 6.5mm bullets range in weight from approximately 85 grains to 160 grains. 7mm bullets range in weight from approximately 100 grains to 175 grains. Both of these cartridges have long necks and can handle the heaviest bullets available, but bullets of about 140 grains are the most popular weight for both calibers. So, for reloaders, there is not much to choose between the 6.5x55 and 7x57.
It is hard to say, on balance, which cartridge is superior. Even on the same type of game it depends on the specific situation (the angle at which the animal is standing, its state of mind, etc.) as to whether greater bullet frontal area or greater sectional density is more desirable, and that is hard to predict in advance. Both cartridges are adequate for all species of North American antelope, deer, sheep, goats, feral pigs, black bear and caribou.
I would summarize the 6.5x55 vs. 7x57 comparison thusly:
Ballistically, the 6.5x55 and 7x57 have many similarities, but they are not identical and each has specific advantages. Both are fine, very well proven cartridges and most shooters will be well served by either.
Copyright 2003, 2012 by Chuck Hawks. All rights reserved.