Behind the Bullet: The .25 WSSM

The .25 WSSM earns its place as a quarterbore that packs .25-06 Remington performance into a case nearly an inch shorter, letting you run it in a compact short action instead of a full-length rifle. Winchester claimed the cartridge would equal the velocity of the .25-06, and the factory numbers back that up: the .25 WSSM 120-grain softpoint leaves the muzzle at 2,990 fps, which is precisely what Winchester’s own .25-06 load delivers with a comparable bullet. That parity in a smaller package is the whole argument for the round.

It handles the work you would ask of any quarterbore. The .25 WSSM is suitable for any game appropriate for a cartridge of its class, with manageable recoil and enough accuracy for hunting. An 85-grain Ballistic Tip load pushed to 3,470 fps stretches it into varmint duty, so a single rifle can serve as both a deer gun and a varmint gun. That versatility, more than any single ballistic figure, is what made it the most popular of the three WSSM cartridges.

Where the WSSM line came from

The Winchester Super Short Magnum is a family of rebated, bottlenecked centerfire short magnum cartridges that the U.S. Repeating Arms Company brought out as a next step beyond the Winchester Short Magnum, trading down to smaller bullets while pushing velocity higher still. Its roots trace to the second surge of magnum development that followed the .300 Remington Ultra Magnum and the .300 Winchester Short Magnum in 1999 and 2001, years that delivered a run of beltless, rimless magnums.

Winchester and Browning teamed up to trim the WSM case down, and what came out looks a lot like the stubby benchrest rounds of the 1970s and 1980s, with the .22 PPC as a close cousin. The engineering leaned on the same ideas that had been winning on the benchrest line, the 6 mm PPC and 6 mm BR Remington among them. The .223 and .243 reached buyers first, both in 2003, and the .25 WSSM joined them in 2004. In performance, the .223 shadows the .220 Swift and 22-250, the .243 lines up with the 6 mm Remington and .243 Winchester, and the .25 tracks the .257 Roberts and .25-06 Remington. A number of writers credit the .404 Jeffery as the family’s parent, or at least its inspiration.

The case up close

The .25 WSSM runs 1.670 inches at the case and 2.360 inches at full cartridge length, firing a .257-inch bullet. Its slightly rebated rim comes in at 0.535 inches, which lines up with the bolt face of the common H&H cartridge family rather than the fatter 0.545-inch base of the .404 Jeffery. The body base measures 0.555 inches, the neck 0.300 inches, and the 30-degree shoulder does the headspacing.

That short, wide shape is the whole idea. Shooters have long chased accuracy with a stubby powder column, and the Short Magnum concept rests on the claim that packing powder short and fat gives you steadier load density and a more even ignition. The theory holds that burning the charge more uniformly should tighten groups and may keep recoil in check through more efficient use of the propellant.

The short-action advantage

The best practical reason to run a .25 WSSM is the action it fits. A .25-06 Remington demands a .30-06-length receiver, the standard or long action. The .25 WSSM, with its case nearly an inch shorter, drops into an existing short action, the same size that serves the 5.56 NATO and .223 Remington family. Some makers have gone further and built extra-short actions for these newer rounds.

Riflemakers treat a short, stiff action as a known path to accuracy over a long one, and a rifle built on it ends up smaller, lighter, and quicker to swing. The trade shows up on paper. A fat case eats into magazine capacity and can hurt feeding reliability, and it leaves a thinner bolt face that is more prone to breaking at the cartridge’s working pressure. That same wide body also gave some rifles fits on the feed ramp, since a short, squat case does not always chamber smoothly.

Why it never caught on

For all it offered, no WSSM cartridge ever took a meaningful share of the market. The plainest explanation is that each one simply duplicates the performance of a cartridge shooters already owned, leaving no real reason to change. The .223 and .243 also picked up an early name for burning out barrels, a hazard that comes with any high-velocity round; Browning now fits its .223 WSSM rifles with chrome-lined barrels to blunt that wear.

The killing stroke came from the courts. Gunwriter Rick Jamison, holder of a patent covering several short magnum designs that looked much like the WSSM rounds, sued Winchester over copyright and patent infringement. On November 2, 2005, the United States District Court for the District of Oregon decided Jamison v. Olin Corporation in his favor, ruling that the Olin/Winchester and Browning WSSM products had used his patented designs without paying for them. Jamison, who had first brought his invention to Olin/Winchester, prevailed. Faced with paying royalties, the companies instead shut down production of every WSSM rifle. According to Phil Massaro, John Lazzeroni’s 7.82 Patriot, a rimless .30-caliber magnum made to run in a short action, went back to the mid-1990s and so came before the Jamison patent.

Living with one today

That lawsuit set the supply situation that still holds. Inside a few years of launch, .25 WSSM ammunition had largely vanished, and stocks for the whole WSSM line fell to almost nothing in the wake of the suit. Factory loads do still surface. Winchester has sold two .25 WSSM offerings through HSM, a 115-grain Berger VLD at 2,831 fps and a 117-grain Sierra GameKing at 2,874 fps. New-old-stock shows up at specialty dealers like Collector Rifle and Ammo, Inc. Interest never fully died off either; by Massaro’s own account of his custom loading work, close to one in every eight or nine orders was for the .25 WSSM.

Handloading is the most reliable way to keep one running, but there is a snag. You cannot form the brass from any other cartridge, so sourcing cases is where the trouble lies. With cases in hand, the tightest groups across the bullet-weight range tend to come from medium-burn powders such as IMR 4064 and Hodgdon’s Varget, and slower choices like Reloader 19 and H414 perform well too. The magnum label aside, a standard large-rifle primer is the one to use, with Federal’s Gold Medal Match GM210M a favorite. Count on handloads to land roughly 100 to 150 fps under comparable .25-06 loads.

The case also fathered a few wildcats. The .358 WSSM, also called the .358 BFG, builds on the .25 WSSM and shoots like the .358 Winchester and .35 Whelen, while Olympic Arms opened the neck up to .308 for the .300 OSSM, which lands between the 30-06 and .300 Winchester Magnum.

The verdict

The .25 WSSM made good on Winchester’s promise: .25-06 ballistics out of a short, stiff action that yields a lighter, faster-handling rifle. By Massaro’s reckoning from working with it, its standing as the pick of the WSSM trio was earned on the range and in the field. Its downfall traced not to any fault in the cartridge but to a patent fight that stopped production and choked off the ammunition supply. If you already own one, handloading and specialty-shop ammo will keep it fed, and it stays a capable quarterbore for deer and varmints alike. If you are shopping new, the honest math is that the .25-06 gives you the same performance with brass and ammunition you can actually find on a shelf.

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