By Chuck Hawks
The old 6.5x55 Swedish Mauser and the newer 7mm-08 Remington rifle cartridges are both popular and well known. This is especially true in North America where the 7mm-08 originated and has become a "top 30" rifle cartridge, and the 6.5x55 has been in the top 30 for years. In much of the rest of the world the 6.5x55 is very well known, while the standby 7mm rifle cartridge remains the 7x57 Mauser, but the 7mm-08 has made inroads.
Since I have already written an article comparing the .260 Remington and 7mm-08 Remington, and another article comparing the 6.5x55 and 7x57, much of the material in this article will unavoidably be essentially similar. The .260 is just a newer version of the 6.5x55, and the 7mm-08 is a newer version of the 7x57.
The 6.5x55 SE
6.5x55
Illustration courtesy of Hornady Mfg. Co.
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. It is covered in detail in an article on the Rifle Cartridge Page.
Despite its age, the 6.5x55 is a modern looking rimless cartridge with a sharp 25-degree shoulder angle. The cartridge overall length (COL) is 3.150", thus it requires an "intermediate" (rare) or standard length action. It has the case and neck length to allow it to efficiently handle long, heavy bullets. Bullet diameter is .264" and for big game hunting the 6.5x55 is at its best with bullets ranging from 120-160 grains, although bullets from about 85-160 grains are available to reloaders.
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 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 7mm-08 Remington
7mm-08
Illustration courtesy of Hornady Mfg. Co.
The 7mm-08 Remington was introduced in 1980 in the Model 700 bolt action rifle. At first sales were slow, probably because it is essentially the ballistic twin of the 7x57, but over time it has caught on. Unlike the 7x57 (and the 6.5x55) there are no ancient or weak 7mm-08 rifles floating around, so commercially manufactured ammunition is loaded close to the SAAMI maximum average pressure of 52,000 cup.
The 7mm-08 is based on a .308 Winchester case necked down to accept .284" bullets. It has a maximum COL of 2.80" and is thus a true short action cartridge. The 7mm-08 is covered in detail in an article on the Rifle Cartridge Page.
For big game hunting, it is at its best with bullets weighing between 120 and 150 grains. Bullets from about 100-175 grains are available to reloaders.
Remington 7mm-08 factory loads drive a 120 grain bullet (SD .213) at a muzzle velocity of 3000 fps and a variety of 140 grain bullets (SD .248) at a MV of 2860 fps. Federal offers a 150 grain bullet at a MV of 2650 fps in addition to standard 140 grain loads. Hornady, Norma, PMC, and Winchester also offer factory loads in 7mm-08, mostly with 140 grain bullets. Reloaders can safely achieve velocity figures similar to the factory loads.
Remington offers the 7mm-08 in the Model 7 bolt action, Model 7600 pump and Model 7400 autoloader, in addition to the Model 700. The 7mm-08 has become a standard short action offering, and is also available in Blaser, Browning, Kimber, Ruger, Sako, Savage, Tikka, Weatherby, and Winchester rifles.
The Comparison
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.
Let's compare bullets of the same weight and type, using 140 grain Nosler Partition bullets as an example. This favors the 6.5x55 in sectional density (and theoretically wound channel depth), but favors the 7mm-08 in bullet frontal area (and theoretically wound channel diameter), assuming that all other factors such as velocity, energy and bullet performance are equal.
Here are the figures for SD and bullet frontal area:
* 6.5mm, 140 grain - SD .289, frontal area .0547 sq. in.
* 7mm, 140 grain - SD .248, frontal area .0633 sq. in.
In terms of wound channel terminal ballistics in soft tissue, the advantage in SD possessed by the 6.5x55 is probably balanced by the 7mm-08's advantage in bullet frontal area. Just bear in mind that when used on tough game with bullets of equal weight, the 6.5x55 has a potential advantage in penetration and the 7mm-08 has a potential advantage in shocking power.
Also remember that bullet design has a tremendous impact on expansion and penetration, and introduces many variables. A fast expanding 6.5mm bullet, such as the 140 grain Nosler Ballistic Tip, will almost certainly create a larger diameter, but shorter, wound channel than a limited expansion bullet such as the 7mm/140 grain CT Fail Safe, also manufactured by Nosler. For most purposes in this article, we will be comparing loads using essentially identical Nosler Partition bullets.
According to the top factory load ballistics as printed in the 2004 edition of the Shooter's Bible, the 7mm-08 can launch the popular 140 grain bullet 71 fps faster than the 6.5x55 with full pressure loads. For the reloader, the difference is probably more like 100 fps for typical maximum loads, but the net result will be similar. We will use the following factory loads for comparison:
* Norma 6.5x55, 140 grain Nosler Partition at MV 2789 fps.
* Rem. 7mm-08, 140 grain Nosler Partition at MV 2860 fps.
This velocity advantage translates to a slight advantage in muzzle energy favoring the 7mm-08. Here are the energy figures (in ft. lbs.) for the 140 grain Norma and Remington factory loads at the muzzle, 100, 200, and 300 yards:
* Norma 6.5x55, 140 grain at 2789 fps - 2419 ME, 2089 at 100 yards, 1796 at 200 yards, 1536 at 300 yards.
* Rem. 7mm-08, 140 grain at 2860 fps - 2542 ME, 2180 at 100 yards, 1860 at 200 yards, 1577 at 300 yards.
The 7mm-08 starts out with a 123 ft. lb. advantage in ME, but at 300 yards that gap has closed to only 41 ft. lbs. This is due to the superior ballistic coefficient (BC) of the slimmer 6.5mm bullet. The Nosler BC figures for their 140 grain Partition bullets are .490 for the 6.5mm bullet and .434 for the 7mm bullet.
This difference in BC will also affect the trajectories of the two loads, where the 7mm-08's velocity advantage is pretty much negated by the superior BC of the 6.5mm bullet. Here are the trajectory figures for our two factory loads, assuming a 200 yard zero:
* Norma 6.5x55, 140 grain at 2789 fps - +1.8" at 100 yards, -7.8" at 300 yards.
* Rem. 7mm-08, 140 grain at 2860 fps - +1.7" at 100 yards, -7.6" at 300 yards.
This is not enough difference to matter in any hunting situation. The trajectory comparison is essentially a tie.
How does all of this affect killing power? The "Optimal Game Weight" (OGW) figures, based on the pioneering work of Edward A. Matunas and published in the Lyman 47th Reloading Handbook, show that with our chosen factory loads the OGW is as follows:
* 6.5x55/140 - 638 lbs. at muzzle, 520 at 100 yards, 422 at 200 yards, 340 at 300 yards, 272 lbs. at 400 yards.
* 7mm-08/140 - 688 lbs. at muzzle, 547 lbs. at 100 yards, 432 lbs. at 200 yards, 339 lbs. at 300 yards, 264 lbs. at 400 yards.
These figures indicate similar killing power. The 7mm-08 has a slight advantage at short and medium range, and the 6.5x55 has a very slight advantage at long range. The OGW numbers cross at 300 yards, where they are virtually identical.
One of the nice things about both of these cartridges is their moderate recoil. They are among the mildest of the all-around rifle cartridges. Since bullet placement is, by far, the most important factor in killing power, most hunters can kill better with a rifle that kicks less.
No doubt this contributes to the sterling record of the 6.5x55 and 7mm-08 in the field. Both are more than adequate for all CXP2 class game, and have proven adequate for CXP3 class game such as North American elk, Scandinavian moose, and tough African plains game in the hands of a careful marksman.
Here are the approximate recoil figures for both cartridges, computed for our comparison factory loads in 8 pound rifles:
* 6.5x55, 140 at 2789 fps - 14.2 ft. lbs.
* 7mm-08, 140 at 2860 fps - 13.9 ft. lbs.
Again we have a virtual tie. The 0.3 ft. lb. difference is well within the computational error of the recoil calculation, since the actual powders used in the factory loads are unknown. For this comparison, I used powder data from the fifth edition of the Nosler Reloading Guide, corrected for the velocity change caused by the 3" difference in the length of the Nosler test barrels.
For reloaders, bullet selection and availability are 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.
Both of these cartridges can handle bullets from 120 to 160 grains with reasonable efficiency, and these are widely available. So, for reloaders, there is not much to choose between the 6.5x55 and 7mm-08 for big game hunting.
The hunter and reloader who wants to use his all-around big game rifle for some varmint or predator hunting during the off season will be able to do so with either caliber. Edition V of Sierra Rifle and Handgun Reloading Data shows that the 6.5mm Sierra 85 grain HP varmint bullet (SD .174) can be driven to a maximum velocity of 3500 fps. The same reloading manual shows that the 7mm Sierra 100 grain HP varmint bullet (SD .177) can be driven to a maximum velocity of 3300 fps. For the varmint and small predator hunter, a lighter bullet with a similar shape and SD at higher velocity will shoot flatter and is probably the better choice. Advantage 6.5x55.
Summary and conclusion
I would summarize the 6.5x55 vs. 7mm-08 comparison thusly:
* If you favor bullet frontal area for increased shocking power, the 7mm-08 has the theoretical advantage.
* If deep penetration is more important to you, the 6.5x55 has the theoretical advantage.
* A reasonable selection of factory loads and reloading bullets are available for both calibers.
* If you are a reloader that already owns another rifle in either caliber, say a .264 Winchester Magnum or a 7mm Remington Magnum, then I would stick with the caliber I already own. You may be able to use the same bullet(s) in both calibers, reducing your inventory costs, and you are probably predisposed to favor that caliber, anyway.
* If you are a reloader who also wants to use your rifle for varmint/predator hunting, the 6.5x55 is perhaps the better choice.
* If you prefer a certain make and model of rifle and it is available in one caliber but not the other, your decision has been made. Getting the rifle you like best is probably more important than the differences between the two calibers.
It is hard to say, on balance, which cartridge is superior. The principle differences are in bullet frontal area and sectional density. 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 a wider wound channel or a deeper wound channel is more desirable, and that is hard to predict in advance.
Both cartridges are recommended for all species of North American antelope, deer, sheep, goats, feral pigs, black bear and caribou, and similar size animals worldwide. They are adequate for elk and moose if the hunter does not attempt to stretch the range and has the skill place his shot carefully, although neither would be my first choice for shooting such large animals.
Ballistically, the 6.5x55 and 7mm-08 are similar. Both are proven cartridges and most shooters will be well served by either.
(Spanish Am war, Boer war, Bell & elephants, ect...)
