Compared: .325 WSM, 8x68S RWS, and 8mm Rem. Mag.
By Chuck Hawks
What we have here is an 8mm Magnum comparison. The .325 WSM, 8x68S, and 8mm Remington Magnum are probably the most widely recognized 8mm Magnum calibers. Here in North America none of them are very popular. The 8mm Rem. Mag. appears to be dying, the 8x68S is practically unknown, and the .325 WSM (a true 8mm despite its name) is too new to have made whatever market impact it will. Regardless of nomenclature, all of these 8mm rifles have a bore diameter of .311-.315" and a groove/bullet diameter of .323".
In Europe, however, 8mm magnums are understood and appreciated, and the 8x68S is reasonably popular, particularly in Germany, France, and Spain. It is the European equivalent of one of the North American .300 Magnums, offering similar killing power and used for hunting the same size animals. Europe is much closer to Africa than is the New World and more available to European hunters, so many Europeans take their 8x68S rifles on African safaris, where they serve admirably as all-around rifles.
The 8x68S is the oldest and most successful of our trio of 8mm magnums. It was introduced in 1940 by RWS of Germany.
The cartridge is based on a large, non-belted magnum case 2.658 inches in length. The maximum cartridge overall length (COL) is specified as 3.425. This is 0.085" longer than the 3.340" COL of the .30-06 Springfield round, and 0.175" shorter than the 3.60" COL of the .375 H&H Magnum cartridge. So the 8x68S is in-between a standard length and a long magnum length cartridge, but closer to the former. It could probably be used in at least some standard length rifle actions.
The rim diameter is .512 inches, larger than the standard non-magnum rim diameter of the 8x57JS or .30-06, but slightly smaller than the rim diameter of standard belted magnum cases like the .300 Win. Mag. The 8x68S has a rebated rim, since the body diameter just forward of the extractor groove measures a fat .524 inch. The shoulder angle is just over 14.5 degrees, much less than the 25 degree shoulder angle of the 8mm Rem. Mag.
The 8x68S is a large capacity, modern looking magnum case with the relatively sloping shoulder of a much older cartridge. When you consider that it was designed after the standard cartridges of the pre-World War II era and before the surge of post war magnums, this becomes understandable. The 8x68S was designed specifically for use in bolt action repeating rifles and, due to its rebated rim design, is not suitable for use in falling block or break-action rifles.
8x68S rifles and ammunition are available in Europe, but seldom seen in the U.S. RWS and Hirtenberger factory loads claim a MV of 3180 fps with a 187 grain bullet and 2985 fps with 196-200 grain bullets. According to Cartridges of the World these velocities are optimistic. European reloading data comes within about 100 fps of these velocities using the lighter bullets, and within about 35 fps of these velocities with 196-200 grain bullets.
Fortunately, the sixth edition of the Hornady Handbook of Cartridge Reloading does include the 8x68S, so reliable reloading data can be taken from that source. The Hornady technicians used RWS cases and Federal primers in a Mauser 66 with a 26 inch barrel for testing. The performance of the 8x68S can be summarized as similar to what you would get if you necked a .338 Win. Mag. case down to accept 8mm (.323 inch) bullets.
8mm Remington Magnum
The 8mm Rem. Mag. was introduced to an uncaring world in 1977. It is based on the full length .375 H&H belted magnum case blown out for less body taper and given a sharper 25 degree shoulder. The maximum case length is 2.850" and the maximum COL is 3.60" It has a standard .532" magnum rim diameter.
This cartridge requires a rifle with a long magnum action which, coupled with its unpopular (in the North American market) 8mm caliber, insured that it would never become popular. After offering their 8mm Magnum in the Model 700 line for a few years, Remington essentially gave up on the cartridge and relegated it to "special order only" status through their Custom Shop.
Originally Remington offered two bullet weights in their factory loads, a 185 grain and a 220 grain. Neither sold very well and both have been discontinued in favor of a single 200 grain bullet. The current Remington 8mm Magnum Premier factory load drives a 200 grain Swift A-Frame PSP bullet (SD .274) at a MV of 2,900 fps. Unlike the factory load figures for our other two contenders, this is an attainable velocity in the 24" barrels of hunting rifles. In fact, the current Remington factory load is on the mild side; some reloading manuals list loads at 3000-3050 fps with 200 grain bullets from 24" barrels.
When it was introduced Remington explained that their new 8mm Magnum cartridge was intended to offer high energy and flat trajectory "without developing excessively uncomfortable recoil." To clarify the "excessively uncomfortable" wording, the cartridge shoots flat and develops an uncomfortable amount of recoil.
This is the newest of the 8mm Magnums, based on the trendy .300 WSM case. It was introduced in 2005 and is available in Browning and Winchester brand rifles. Intentionally misnamed as a marketing ploy, this is a true 8mm cartridge, shooting the exact same .323" diameter bullets as any other 8mm.
The .325 WSM was designed to work in short (.308 length) action rifles, which explains its rebated rim, short fat body, short neck, and sharp 35 degree shoulder angle. Like other WSM cartridges, the .325 is based on a drastically chopped .404 Jeffery case. The maximum case length is 2.10" and the maximum COL is 2.860".
Winchester has offered three factory loads for the .325 WSM. These include a 180 grain Ballistic Silvertip bullet at an advertised MV of 3060 fps, a 200 grain AccuBond bullet at a MV of 2950 fps, and a 220 grain Power Point bullet at a MV of 2840 fps.
Chronograph results indicate that in the 24" barrels of Model 70 rifles these loads deliver about 75 fps lower velocity than claimed. In the 23" barrels of Browning A-Bolt II rifles these loads deliver about 100 fps less velocity than claimed. Apparently, with the .325 WSM, Winchester has returned to the bad old days of inflated factory load ballistics.
Like the other 8mm Magnum cartridges, the .325 WSM kicks like a mule. Because the Winchester Model 70 and Browning A-Bolt II rifles offered in .325 are about a pound lighter than traditional 8mm Magnum rifles, the effect of recoil is more pronounced.
Since all of these calibers use 8mm (.323") bullets in weights up to 220 grains, there is no difference in the sectional density (SD) or bullet frontal area. So we can eliminate those factors from consideration.
What we can objectively compare is velocity, energy, trajectory, and recoil with a selected bullet weight. Toward the end of this comparison we will also briefly address the availability of rifles, ammunition, and other factors regarding these cartridges.
For these three 8mm magnums, bullets from 150 to 220 grains are usually selected for big game hunting, and bullets weighing around 200 grains seem to be the most popular. So for comparison purposes I am going to standardize on a 200 grain bullet, in this case the excellent Nosler Partition spitzer, which has a ballistic coefficient of .426 and a sectional density of .274.
In order to be as fair and accurate as possible, and to avoid skewing the results because of inflated factory ballistic claims, I am going to use independently chronographed velocities from either factory loads or maximum reloads for comparison. These are velocities that can reasonably be expected from the 24" barrels of hunting rifles chambered for these cartridges.
Here are the loads that we will compare showing velocity at the muzzle and at 200 yards:
Obviously the 8mm Rem. Mag., with the biggest case, can also attain the highest velocity at the same maximum average pressure. At 200 yards the 8mm Rem. Mag. has only a 46 fps advantage over the 8x68S, but a 113 fps advantage over the .325 WSM. All three cartridges are in the same general ballpark, however, and there is little practical difference in velocity between the 6x68S and 8mm Rem. Mag.
Here are the kinetic energy figures in foot-pounds for our selected loads at the muzzle and at 200 yards:
Energy is an important factor in killing power. As kinetic energy is a function of mass and velocity, it is no surprise that the 8mm Rem. Mag. delivers the most energy to the target at all ranges, followed by the 8x68S and .325 WSM in that order. At 200 yards there is a 102 ft. lb. energy gap between the 8mm Rem. and 8x68S, and a 200 ft. lb. gap between the 8x69S and .325 WSM. The difference is not great, but it is fair to conclude that the .325 WSM trails in this area.
Muzzle velocity and the ballistic coefficient of the bullet are the primary factors determining the trajectory of any rifle bullet. Sighting-in a rifle with a scope mounted 1.5" over the bore so that the bullet does not deviate more than 3" above or below the line of sight gives us its maximum point blank range (MPBR). Thus the MPBR is the distance at which the bullet falls 3" below the line of sight. So zeroed, the trajectory of our three comparison loads looks like this:
These trajectories are all reasonably close. A 4 yard gap separates the 8x68S from the flat shooting 8mm Rem. Mag., and there is an additional 7 yard gap in MPBR between the 8x68S and the .325 WSM.
I computed the recoil energy for an 8 pound (including scope) .325 WSM rifle shooting a 200 grain bullet at an honest MV of 2875 fps at 31.4 ft. lbs. Due to its lightweight rifles, the .325 WSM is definitely uncomfortable to shoot.
The recoil of a 9 pound 8x68S rifle shooting a 200 grain bullet at a MV of 2950 fps is about 29.1 ft. lbs. The extra rifle weight helps to moderate recoil, although this is still way over the 20 ft. lbs. maximum most shooters can tolerate, and nearly twice the preferred 15 ft. lbs. maximum recoil.
Remington rifles in 8mm Rem. Mag. caliber usually weigh about 8.5 pounds with a scope, and the recoil of such a rifle shooting a 200 grain bullet at a MV of 3000 fps amounts to about 34.5 ft. lbs. Shooting the big case Remington cartridge in a medium weight rifle should get anyone's attention.
Considering performance and recoil, the 8x68S seems like the best deal. However, none of these 8mm magnum rifles are what you would call fun to shoot.
Factory loaded ammunition is expensive for all of these calibers, both in Europe and North America. Most of the smaller sporting goods outlets in the U.S. do not regularly stock any of these calibers. Full line gun shops may carry a limited amount of .325 WSM and 8mm Rem. Mag. ammunition, but 8x68S ammunition is hard to find.
In Europe the situation is reversed, with 8x68S RWS ammo available from the larger emporiums, but 8mm Rem. Mag. and .325 WSM ammunition very thin on the ground. In parts of Africa the 8x68S is fairly common, but the .325 WSM and 8mm Remington Magnums are seldom encountered.
As was mentioned earlier, anyone who shoots one of these calibers should be a reloader. Once a reasonable number of cases are acquired it will not be hard to assemble reloads for any of these calibers. Reloading dies are available from the usual sources. Large Rifle Magnum primers and medium slow burning powders are generally called for.
The supply of 8mm bullets in North America is not extensive, but it is adequate. Among the major independent U.S. bullet makers, Barnes provides 8mm solid copper X-Bullets weighing 180 and 220 grains. Hornady offers 125, 150, 170, 195, and 220 grain bullets in .323" diameter. Nosler makes 180 and 200 grain bullets. Sierra offers 150, 175, 200, and 220 grain bullets. And Speer provides 150, 170, and 200 grain 8mm bullets.
It is not easy to find a rifle in any of these calibers in the U.S. The most available alternative would be the .325 WSM, as Browning and Winchester dealers abound. Many dealers don't stock .325 rifles, but they can order them. The price should be similar to the same brand and model in .300 WSM caliber.
Any Remington dealer should be able to special order an 8mm Magnum rifle from the Remington Custom Shop for a customer who wants one, but only specialty gun shops will usually bother to do so. Expect to pay a premium price and be prepared for delays.
I understand that in Europe 8x68S rifles are not hard to find. I believe that Blaser, Mauser and perhaps other brands of rifles are chambered for the cartridge. But unfortunately, even the European rifle makers who export to the U.S. do not usually include the caliber in their export line. This is a serious problem for a North American buyer who yearns to own an 8x68S rifle. Perhaps one of the European makers could be persuaded to ship an 8x68S rifle to their U.S. distributor. Once again, delays and a premium price should be expected.
An alternative to ordering a factory built rifle in one of the 8mm magnum calibers would be to order it from a custom rifle maker. This will cost more than most factory built rifles, but you can get the caliber you want in a rifle configured exactly as you prefer.
The .325 WSM was designed specifically for short magnum actions. There are not too many of those around, but there are some. The 8x68S could probably be adapted to most standard length magnum actions, and there are many of those. The 8mm Remington Magnum requires a long magnum action, which is less common than the standard length variety, but more common than short magnum actions.
The difference between a rifle with a short magnum action and a standard length magnum action is about 1/2" in length and 2 ounces in weight, assuming that barrel length, length of pull, and other dimensions are the same. The difference between a rifle with a standard length magnum action and a long magnum action is about another 1/2" in length and two more ounces.
The importance of 1/2" and 2 ounces is a subjective matter, it's a big deal to some shooters and unimportant to others. I am inclined to think that, for a magnum bolt action hunting rifle, shorter overall length is desirable (if other dimensions remain the same) because it makes the rifle a little easier to handle and carry, but that less weight is undesirable, as it increases the effect of recoil.
Big Game Hunting
So what can a big game hunter do with an 8mm magnum rifle? The answer is pretty much whatever he or she would do with a similar .300 Magnum rifle. In both a .300 and 8mm magnum the light 150 grain bullets would be used for long range shooting of CXP2 class game. The 170-180 grain bullets would be a good all-around choice for mixed bag hunts involving CXP2 and CXP3 class game. And the heavy 200-220 grain bullets would be preferred specifically for CXP3 class or thin-skinned dangerous game. The 8mm bullet of any given weight will have greater frontal area, but the .300 bullet will have greater sectional density. In terms of killing power, the two pretty much cancel each other out if the velocity and energy are the same.
With one exception: The .325 WSM should not be chosen if dangerous game is on the menu. It has adequate killing power for big cats and the great bears. But its case design makes it less reliable in all types of rifles. Because of its rebated rim and short fat case design it is more prone to feeding problems from the magazines of repeating rifles than the other two cartridges, and its rebated rim also makes it more difficult to extract and eject from break-open and falling block rifles.
Since the 8x68S and 8mm Remington Magnum offer equal or superior killing power and greater reliability when used in bolt action rifles, they should be the obvious choices for hunting dangerous game. The difference is reliability is not great, but it exists.
The .325 WSM, 8x68S RWS and 8mm Remington Magnum are generally comparable in overall performance. I conclude that the 8x68S is probably the best all-around cartridge, but not by much. For the European or African hunter it would be the obvious choice.
For the North American elk hunter, rifles in .325 WSM will be cheaper and easier to find or order. If I just had to have an 8mm magnum rifle, I'd probably go with a Winchester Model 70 Classic Laminated, because at 7.75 pounds it's the heaviest rifle available in the caliber, provided that I did not have to contend with grizzly, brown, or polar bears.
For hunters in other parts of the world, such as South America, Asia, and Australia, I suspect that none of these cartridges, or rifles chambered for them, will be easy to come by. I think I'd eschew all of the 8mm magnums in favor of some better known cartridge of similar power. Perhaps a .300 Magnum for all-around use or, for heavy game, the .338 Winchester Magnum. In fact, now that I think about it, that is pretty good advice for hunters in North America and Europe, too!
Copyright 2005, 2012 by Chuck Hawks. All rights reserved.