SPORTS STARS: THE WSSMs (WINCHESTER SUPER-SHORT MAGNUMS)

Created on 14th May 2009

LAURIE HOLLAND's on steroids - oh no, sorry, he's investigating the so-called ‘PPCs on steroids'

I recently featured the WSMs, which give magnum performance from .308W length designs and are employed in rifles with short, stiff actions. Winchester tried to build on its success with three still shorter designs in smaller calibres: the .223, .243 and .25WSSMs, appearing between 2003 and 2005. As before, they were joint developments by Winchester (the ammunition company) and the sporting products divisions of multinational arms manufacturer FN-Herstal, the US Repeating Arms Co (Winchester brand rifles) and Browning Arms. The 2003 launch of .223 and .243WSSM was accompanied by a range of new Winchester Model 70 and Browning A-Bolt models that cover every American sporting need, from long-range varmints to medium-sized deer. Both employ actions tailored to the WSSM's COAL of 2.36", a half-inch reduction over standard ‘short-action' models. With American shooters conditioned to believe that shorter equals better, the manufacturers had to make a virtue out of necessity as the truncated actions were needed to get such short, fat cartridges to feed.

Steroids

The WSSMs share a 1.67" long case but are very fat in relation to their length, retaining the WSMs' rear-end with a 0.535" rim and 0.555" body diameter. (The comparable .243 Winchester case is 2.045" long with a case-head diameter of 0.473".) There is little taper, the inch-long body section reducing by eleven thousandths of an inch, considerably less than on comparable cartridges such as the 6PPC and 6BR. The WSM's 35º shoulder angle is reduced to a gentler 28º, also probably down to the magazine operation and feed issue. A common description of the WSSMs is ‘PPCs on steroids', the manufacturers playing this card to those who believe case shape is entirely responsible for this precision cartridge's legendary accuracy and ballistics.

High velocity

The third key feature of the WSSMs is high performance. The .224" calibre version far outperforms the .22-250 Remington and pips the .220 Swift with 50-55gn bullets. The .243WSSM improves on the older .243W and 6mm Remington MVs by a worthwhile amount too. The objective with the .25WSSM (0.257" calibre) model was to equal .25-06 Remington factory load performance, which it just about does despite the latter using the large .30-06 Springfield case. All three employ a 10" rifling twist rate: the .223 model is able to handle 70-75gn bullets, the other two are as per the older .243W and .25-06R designs with 100-105 and 117-grainers respectively.

Coming from such a small cartridge, performance is surely down to the PPC form factor? Not really, as the case has more capacity than you might think, matching that of the .308 and .243W. This gives the .223WSSM nearly 40% more powder space than the .22-250R, explaining its 3,850fps MV with 55gn pills, a near 300fps increase. But how does the .243WSSM produce an extra 150fps over the same capacity .243W when factory loaded with the 95gn Nosler Ballistic Silvertip? This must be down to the PPC-form effect? Well, maybe not - rather an MAP raised from 60,000 to 65,000psi and the manufacturer loading ammo up to the hilt while restricting it in the older cartridge. To cope with these pressures, the WSSM case is massively constructed, the .243 version weighing in around 40% more than the physically larger .243W, even the neck having 0.020"-plus thick walls.

Grounded

As Americans say, there ain't no such thing as a free lunch, and if you run cartridges at 65,000psi there is a price, notably rapid barrel heating and wear. Scores of ‘experts' on blogs and elsewhere branded the .223WSSM version a ‘barrel burner' before they'd even touched a rifle, which is a not unreasonable assumption with 50gn or even larger powder charges of super-hot and high-pressure gas pushed down the little bore. Actually, Browning and USRAC overcame this potential problem by chrome-plating bores borrowing parent FN-Herstal's expertise. At any rate the WSSMs are no worse than other hot, high-velocity factory numbers and .223WSSM factory barrels last around 1,500 rounds unless abused by rapid fire when red-hot, the .243 lasting a bit more, probably not far short of the .243W's 2,000-round life. The minimal body taper allied to massively thick brass does create a problem with poor case seal in the chamber, giving sooted cases and actions, plus hard bolt opening and case extraction. Handloading them down a bit alleviates the extraction, if not sealing problem, but the .243 version then only gives .243W performance. Moreover, super thick-walled cases never do much for accuracy. Factory ammunition is very ‘hot', only loaded by Winchester, and expensive compared to older competitors, costing around £1.30 a bang.

Five years after their introduction, no other manufacturer has adopted the WSSMs despite Savage allegedly thinking hard about it. Throw in USRAC's demise, and Browning A-Bolts are the only factory rifles now chambered for the cartridges. User feedback is mixed - some are happy, others complain of poor feed, difficult extraction and indifferent accuracy even with handloads. There was great excitement in American circles at the time of the launch, but this has long since dissipated, and it is now unlikely these cartridges will ever take off.

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