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Winchester’s Super Short Magnums

by Jon R. Sundra   |  January 4th, 2011 2

Going short, Winchester announces the .223 and .243 WSSMs


Like other short, fat case designs, the new cartridges have a very efficient and consistent powder burn, giving true magnum performance.

The Winchester Ammunition folks sure have pulled a fast one on us. By “us” I mean industry people who, since the introduction of the .270 and 7mm Short Magnums this past year, have been speculating as to what the next addition to the line would be. Some, including me, thought it would be a .25 caliber. Except for Remington adopting the long-time wildcat .25-06 back in 1969 and the proprietary .257 Weatherby Magnum of 1943, the last commercial .25-caliber cartridge to be introduced was the .257 Roberts in 1934.

There were a few who thought we’d see a 6.5mm, what with Winchester having achieved some success in the late 1950s and early ’60s with its .264 Win. Mag. Most, however, were pretty sure it would be a .338. In any event, whatever caliber it turned out to be, virtually no one gave a thought that it would be anything but the basic .300 WSM case necked either up or down.

Well, the guys in East Alton fooled us all. Not only did they not unveil a new WSM cartridge in .257 or .338, they didn’t introduce another WSM at all; rather, they rolled out two new rounds based upon–would you believe–further-shortened versions of the Short Magnum case!

Designated as the .223 and .243 WSSM (Winchester Super Short Magnums), both are kind of like grown-up versions of the .22 and 6mm PPCs. I mean, these cartridges are really fat relative to the .555-inch head diameter of the case on which they’re based. I’ll tell you right now, if these cartridges ever start looking normally proportioned to you, an ol’ fashioned .270 or .30-06 is going to look like a pencil in comparison.

At this writing, the nominal ballistic specs have not been established, but Winchester states that the targeted velocities for the .223 WSSM “. . .will be roughly 200 fps faster than comparable .22-250 Remington offerings.” I’m assuming the performance of the .243 will also be somewhere in the neighborhood of 200 fps faster than the .243 Win. with bullets of similar weight.


.243 WSSM, .243 WIN., .223 WSSM, .22-250 REM., .223 REM.

Interestingly, Winchester did not choose the exact same case for these rounds. Although both cases are of the same 1.67-inch length, the .223 version has a longer neck and a shorter body than the 6mm. I’m glad to see that Winchester hasn’t compromised with these two rounds by simply necking down the .243 version to .224. Obviously, they felt that optimum performance for the .223 would be achieved with a case having slightly less volume than that used for the 6mm.

No displacement specs of these cases were available at press time, but based on my calculations, the longer-necked, shorter-bodied .223 has about 10 percent less powder capacity than the .243. Initially, three loadings are being offered in each caliber: For the .223 it’s a 55-grain Ballistic Silvertip in the Supreme line and in Super-X brand, 55- and 64-grain Power Points. The two 55-grain slugs are, of course, highly frangible and meant exclusively for varminting. The 64-grain Power Point, however, is designed for use on smaller big game such as deer and antelope and should be a favorite with the many Texans in particular who swear the .22-250 and .220 Swift are perfect for those applications.

Of the three loads to be offered in the .243 WSSM, only one, the 55-grain Ballistic Silvertip in the Supreme line, will be a varmint load; the other two are both game loads consisting of a Supreme 95-grain BS and a Super-X 100-grain Power Point. You’ve got to figure that, based on case volume, whatever the .243 Win. will do at 200 yards, this new .243 WSSM will do at 300–in all three loadings.


Three action lengths for the Browning A-Bolt, from top: standard, short and the new super short.

As I alluded to at the outset, these rounds represent a sort of graduate school of cartridge design theory. Just as the .22 and 6mm PPCs proved that short, fat powder columns burned more efficiently and produced less muzzle turbulence, more consistent velocities and consequently a higher level of accuracy, these new Winchester SSMs may well write a new chapter in accuracy at higher velocity levels.

As newsworthy as these new super-short magnums are, they’re only half the story. Obviously, you’ve got to have someone chambering for these new cartridges, and as I’m sure you’ve already guessed, Browning will be doing just that with its A-Bolt line and USRAC with its Winchester Model 70, just as both companies did with the original WSMs. After all, both are owned by the same parent company, and both have strong historical ties with Winchester Ammunition.


The two new Super Short Magnums will have about a 200-fps edge over the .22-250 and .243 Win., and both should be dynamite varmint rounds.

At this point, I’m sure you’ve already assumed–as I did–that both Browning and USRAC would be using their respective short actions as the basis for these rifles. You know the drill: They’d shorten the bolt travel by using a different bolt stop and shorten the magazine by fitting a baffle at the rear of the box, just as they do now with their short actions when they chamber for the .223 or .22-250. Wrong again. Both Browning and Winchester have designed a new, even shorter action specifically designed around these super-squat cartridges. In fact, both are about 1/4 inch shorter than the existing short actions of both makers. That means these new rifles will not only be 1/4 inch shorter overall (assuming equal barrel lengths) but will have about 1/4 inch less bolt travel and weigh about 1/4 pound less.

Don’t forget too that, all other things being equal, these shorter receivers will be stiffer, which is another plus in the potential accuracy department. Combine all that with the fact that the standard barrel length for the Model 70 in sporter configuration will be 22 inches and for the A-Bolt, 21 inches, and you wind up with guns
weighing around six pounds. Even at that, recoil will still be light enough so as to not be a problem for even young shooters and women.

The Model 70 will be offered in two sporter-weight versions, Featherweight and Black Shadow, and in the Coyote, a 24-inch, heavy-barreled varminter. In the A-Bolt it’s the same story–the Varmint version will wear a heavy, 24-inch barrel, while the sporter versions, consisting of the Composite, Stainless and Medallion models, will sport 21-inch spouts.

Yes indeed, it looks like 2003 will be another very interesting year for us rifle geeks.

  • ellis

    why does my win 70 243 wssm wants load 2 shells or jams when l load a shell?

  • jackie Danials

    I have a Model: SRV,MODEL 70,243 WSSM. I took it in trade on some work some time ago. Judging by the scope that is on it I assume it was sold at walmart. Does anyone know what it's worth.

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