8mm Revisited: The .325 WSM

By Chuck Hawks

The .325 Winchester Short Magnum (WSM) was introduced as the first new cartridge for 2005. The word is that Winchester (Olin) tried to develop a .338 WSM, but ran into technical difficulties because of the short, fat, short neck design of the WSM case and the length of .338 bullets. In the end, the closest thing that they could manage was an 8mm cartridge.

The ".325" nomenclature of the new cartridge is both unusual and inaccurate. It is actually a .31 caliber according to the traditional system by which the .270 WSM and .300 WSM were named. The former has a bore diameter of .270" and the latter a bore diameter of .300". Thus the new cartridge should have been named the .315 WSM, as that is its approximate bore diameter.

Nothing about the .325 WSM is actually .325" in diameter, and unlike the .338 Win. Mag. and .350 Rem. Mag. with which it is intended to compete (by the Winchester marketing department, at least), it is not a medium bore cartridge and should not be regarded as such.

Even if it had been possible to make a true medium bore WSM cartridge, it would be hard to see the point. The sharp shoulder, short fat case, and rebated rim of the WSM design makes it less reliable than standard cartridges in terms of function in all types of rifles. Any WSM cartridge is therefore a poor choice for hunting dangerous thin-skinned game, which is one of the primary purposes of most mediums. And the existing .300 WSM is adequate for non-dangerous CXP3 class game (elk, moose, etc.).

The .325 WSM is actually a small bore hunting cartridge very similar to the various short and standard length .300 Magnums, or any of the standard European 8mm (7.9mm) cartridges. Ballistically the .325 WSM is nearly identical to the 8x68S. See my article "Compared: .325 WSM, 8x68S, and 8mm Rem. Mag." on the Rifle Cartridge Page for more on that subject.

Dimensionally the .325 WSM is identical to the .300 WSM, except that the .325 case is necked-up to accept regular 8mm (.323" diameter) bullets. The shoulder angle is 35 degrees, the rim diameter .535", and the base diameter .555". The maximum case length remains 2.10" and the cartridge overall length remains 2.860".

Reloaders should note that there is a much smaller selection (at least in North America) of .323" bullets than of the .308" bullets used in all .300 Magnum cartridges. 8mm calibers have never caught on in North America because they are so similar to the vastly more popular .30 calibers.

Compared to the .300 WSM, the .325 has a small advantage in bullet cross-sectional area, and a small disadvantage in sectional density (SD) for any given bullet weight. The relationship between the two cartridges is basically the same as the relationship between the .30-30 Winchester and .32 Winchester Special, which are also based on the same case. As has been recognized by knowledgeable shooters for over 100 years, these advantages pretty well cancel each other out. The net result in killing power is about a wash. What the .300 WSM will do the .325 WSM will do, and vice-versa.

The .325 WSM might have greater appeal in Europe, where 8mm rifles are far more popular than they are in North America, except for the fact that superior 8mm Magnums have been available to European shooters for many years. And, because of its misleading name, many European shooters may not even realize that the .325 is an 8mm cartridge. I think that it is reasonable to assume that if the .325 WSM were aimed primarily at the European market, it would have been called the "8mm WSM."

Consider these facts about the .325 WSM:

  1. Winchester's original intention was a medium bore .338 WSM.
  2. After the failure of that project, and unwilling to write off their investment of time and money, they settled for a .315 bore cartridge instead.
  3. A .315 has no practical advantage over the previous and far more popular .300 WSM, or any other .300 Magnum cartridge.
  4. Winchester intentionally misnamed the new cartridge to make it sound closer to a medium bore than it really is. (If they had been honest about it and named it the .315 WSM or 8mm WSM I would not be so hard on them.)

Seen in that light it becomes clear that the .325 WSM is superfluous in the greater scheme of things. It is merely a marketing ploy to sell a few additional Winchester rifles and cartridges. The inescapable conclusion is that, fundamentally, the new cartridge is an exercise in "smoke and mirrors," an attempt to mislead the American buying public about the new cartridge. That is, to pass off the .325 WSM as the short action medium bore cartridge that Winchester (Olin) actually failed to develop.

Unfortunately, Winchester has found willing accomplices in the mainstream firearms press. Almost entirely dependent on advertising from the "big guns" (so to speak) in the industry for their survival, the popular gun and outdoor magazines have lavished praise on the .325 WSM.

I recently read an article where the author constantly referred to the .325 WSM as a "big bore" cartridge, which--by definition--it is not. The same article incorrectly stated that it was a .325 bore, and pretended that the .325 WSM is comparable to the .338 Win. Mag. for hunting large animals, which is BS of the purest ray serene. This author also tried to perpetuate the myth that the WSM short magnums kick less than belted magnums of equal capacity and performance, which would require a repeal of the laws of physics to be true. It must have been difficult for the author to pack so much misinformation into one article just to please his editor and a big advertiser. I am glad that I don't have to work under those conditions!

That type of article almost always involves a "field test" in which the .325 WSM is used to kill some innocuous medium-size animal. Naturally, with proper bullet placement, the animal dies in a satisfactory manner. (There is no doubt that the .325 WSM has plenty of killing power.) Not mentioned is that the animal could have been killed just as efficiently with the .300 WSM, or with any other .300 or 8mm Magnum cartridge, as well as a number of standard (non-magnum) cartridges. And nowhere in the pages devoted to these articles is there any mention of the disadvantages inherent in the design of the WSM family of cartridges.

Yet it is becoming apparent that, for technical reasons (i.e. case shape), the much-ballyhooed Winchester Short Magnum is a rather limited design. Winchester (Olin) tried, and failed, to neck it down to make a viable .25 caliber magnum (thus the introduction of the .25 WSSM instead of a .25 WSM), and failed again when they tried to neck it up to .33, the smallest of the medium bore calibers. Winchester technicians have admitted that the WSM case was optimized for .30 caliber bullets, and that its efficiency falls off rapidly as the caliber is decreased or increased. Evidently the utility of the WSM case lies between .27 caliber and .31 caliber, period.

Contrast that with the conventional short action .308 case, which has proven technically feasible and commercially viable in calibers from .24 to .35, or to the standard length belted magnum case, which has proven both feasible and viable in calibers from .25 to .45. Such comparison does not flatter the WSM design. The trendy short, fat WSM shape has turned out to be a serious liability.

That said, the .325 WSM is a satisfactory cartridge for hunting non-dangerous CXP2 and CXP3 class game, animals from the size of deer and antelope to elk and moose, as long as the shooter can tolerate the substantial recoil. But let's not pretend that the .325 WSM is a medium bore cartridge, or that it offers anything new in terms of ballistics, or any particular advantage over existing .300, .303, and 8mm short and standard length magnum cartridges.

Winchester factory loads for the .325 WSM include a 180 grain Ballistic Silvertip bullet and a 200 grain Accu-Bond bullet in their premium Supreme ammunition line. In their standard Super-X line they offer a 220 grain Power Point bullet.

The 180 grain BST bullet has a catalog muzzle velocity (MV) of 3060 fps and muzzle energy (ME) of 3743 ft. lbs. The 100 yard figures are 2841 fps and 3226 ft. lbs. At 200 yards the figures are 2632 fps and 2769 ft. lbs. And at 300 yards the claimed figures are 2432 fps and 2365 ft. lbs.

The 200 grain Accu-Bond bullet has a catalog MV of 2950 fps and ME of 3866 ft. lbs. The 100 yard figures are 2753 fps and 3367 ft. lbs. At 200 yards the figures are 2565 fps and 2922 ft. lbs. And at 300 yards the claimed figures are 2384 fps and 2524 ft. lbs.

The 220 grain Power Point bullet has a claimed MV of 2840 fps and ME of 3941 ft. lbs. The 100 yard figures are 2605 fps and 3316 ft. lbs. At 200 yards the figures are 2382 fps and 2772 ft. lbs. And at 300 yards the claimed figures are 2169 fps and 2300 ft. lbs. All of these Winchester velocity figures are averages taken from a 24" test barrel.

The 200 grain Accu-Bond bullet, a bonded core design, will probably prove to be the most popular factory load for hunting large game. This boat-tail, plastic tipped bullet has a very high ballistic coefficient (BC) of .477; its SD is .274. Chronographed from the 23" barrel of a Browning A-Bolt II rifle, the actual MV of the Winchester 200 grain factory load proved to be about 100 fps slower than claimed. The chronograph results from the 24" barrel of a Winchester Model 70 proved to be about 75 fps slower than claimed.

Hodgdon reloading data shows that a 180 grain Nosler Ballistic Tip bullet can be driven at a MV of 2808 fps by 62.0 grains of H414 powder at a MAP of 54,400 PSI. A maximum load of 65.5 grains of H414 will drive the same bullet at 2946 fps with a MAP of 62,000 PSI. These loads were developed using Winchester cases, WLRM primers, and were chronographed from a 24" test barrel.

The .325 WSM will be offered in the usual selection of Browning and Winchester rifles. Browning A-Bolt II Models will come with 23" barrels (except for the 22" barrel of the Micro Hunter), and Winchester Model 70's will come with 24" barrels. All have 3 round magazines.

Recoil tables that I saw indicated that the .325 WSM should deliver about 25-26 ft. lbs. of recoil energy shooting a 200 grain bullet from a 9 pound rifle. That is typical recoil for powerful 8mm rifles.

Unfortunately, the usual Browning and Winchester .325 hunting rifles should weigh between 7.25 and 8.25 pounds, including a scope, and will kick much harder than a typical 9 pound 8mm Magnum rifle. Drive a 200 grain bullet from an 8 pound .325 WSM rifle at an honest 2900 fps and the recoil energy will be around 31.4 ft. lbs. For comparison, that is much more than the approximate 26.8 ft. lbs. of recoil delivered by a .350 Magnum caliber Remington Model 673 rifle with an all-up weight of 8.5 pounds shooting 200 grain factory loads.

Compared to the .300 WSM, velocities with bullets of equal weight should be slightly higher in the new 8mm cartridge because of its slightly larger bore diameter. Velocities with bullets of similar SD will be lower because such bullets must be heavier. (A .30 caliber, 180 grain bullet has a SD of .271, much the same as the SD of a 200 grain 8mm bullet.)

Despite these minor differences, the down range the trajectory of the .300 WSM and .325 WSM cartridges will be about the same, depending on what bullets are compared. The trajectory of a .325 WSM rifle shooting a 180 grain Nosler Ballistic Tip bullet at an honest MV of 2975 fps should look like this: +2.6" at 100 yards, +2.0" at 200 yards, 0 at 245 yards, -4.1" at 300 yards, and -16.8" at 400 yards. The maximum point blank range (+/- 3") of that load is 289 yards.

Reasonable bullets for medium size game like deer and pronghorn antelope will weigh about 150 grains. The 170-180 grain 8mm bullets should be a good choice for all-around use and mixed bag hunts. And for heavy game the 200-220 grain bullets can come into play. Not surprisingly, these are the same bullet weights recommended for the same purposes in the various .300 Magnums.

The performance of the .325 WSM is between that of the 8mm-06 and 8mm Remington Magnum. Fans of 8mm rifles should take it to heart, for it is a short action cartridge that is suitable for a wide variety of CXP2 and CXP3 class game.

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Copyright 2005, 2012 by Chuck Hawks. All rights reserved.