Could This Cartridge Case Revolutionize Hunting?

Sig developed its Hybrid case technology as part of its bid to secure the United States Army's Next Generation Squad Weapon Program (NGSW). Dubbed the “.277 Fury,” the cartridge they designed sports a steel case head connected to a brass body via an aluminum locking washer.

Why a steel case head? Because that’s the first place a cartridge fails. Replacing the usual brass portion with steel allowed Sig to load the .277 Fury to a whopping 80,000 psi–a full 14,000 psi higher than the previous maximum allowable SAAMI-approved pressure.

The .277 Fury is a new cartridge, but that Hybrid case technology can be used to manufacture cases for other cartridges as well. What would happen, hunters wondered, if those Hybrid cases were used to create a .308 Win. Fury, 6.5 Creedmoor Fury, or .270 Win Fury? Those cases could be loaded to pressures well beyond what is safely possible with all-brass cases, and the resulting velocity gains could be tremendous.

Or, in the words of Dan Horner, “revolutionary.”

Horner is a world-class competitive shooter, former Army sniper, and a Pro Shooter for Team Sig Sauer. Sig hasn’t released official data on how Hybrid cases perform in other cartridges, but Horner was able to do his own initial testing. What he found is that hunters can achieve magnum-level performance with standard small-action cartridges using the Hybrid case technology.

He chose the .260 Remington as his test cartridge, which uses 6.5mm bullets. He found that while a standard .260 Rem. cartridge fires a 143-grain bullet 2,780 feet-per-second (fps), a .260 Rem. with the Hybrid case can increase that velocity to 3,068 fps.

“Even in the very limited amount of testing the hybrid casing allowed me to take the small frame of the .260 Remington and perform head-to-head with the 6.5 SAUM,” he wrote in a report on his testing reviewed by MeatEater. “The 6.5 SAUM is touted as the pinnacle cartridge for a short action rifle. The new hybrid case allows us to be equal to, if not exceed, its capabilities.”

The Hybrid .260 Rem. does this while having 30% less case capacity than the 6.5 SAUM.

Image courtesy of Dan Horner.

Horner did not measure the pressure in the chamber, but he saw “absolutely no signs of over pressure.” The primers looked “perfect” and the cases looked “brand new.” He stopped increasing the powder charge once he reached 3,068 fps simply because that was all the velocity he needed to balance maximum terminal performance with barrel life and felt recoil. Theoretically, the cases could be loaded to even higher pressures.

The benefits in the field are obvious. By increasing bullet velocity, Hybrid cases decrease bullet drop and increase bullet energy downrange well beyond a conventional .260 Remington.

.260 Rem., conventional vs. hybrid. Images courtesy of Dan Horner.

What’s more, the increased pressure did not impact accuracy. Horner shot a 0.82-inch group at 100 meters and a 2.86-inch group at 300 meters using the Hybrid .260 Rem. More testing needs to be done to verify these results with other cartridges, and accuracy is highly dependent on a rifle’s barrel and action. But the initial results are extremely promising.

“I think there is a HUGE amount of potential for this technology in the hunting world,” Horner concluded.

Safety Concerns

If you’re hoping to go out and buy a set of Hybrid cases to create your own souped-up cartridges, pump the brakes.

First, you’ll have trouble finding what you’re looking for. Sig hasn’t released any other Hybrid cartridges beyond the original .277 Fury, they don’t sell standalone cases (though pulled cases can be found online), and there isn’t any official loading data available. A spokesperson told me that the company plans to release a .277 Fury loaded with Open Tip Match bullets, but she couldn’t give me a timeline for releasing other Hybrid cartridges.

When they do, the company plans to tread carefully. The Hybrid cases can be loaded beyond standard pressures, but that doesn’t mean a rifle’s chamber will be able to handle it. Horner used a Surgeon action and a Douglas barrel to complete his testing, and he was apparently confident that the rifle could withstand increased pressures.

But not all rifles are created equal. The obvious danger is that someone buys a box of .260 Rem. Fury cartridges (or loads their own) and tries to fire them through their granddaddy’s old deer rifle. The gun may be fine… or it may not. If it’s not, that hunter isn’t likely to get out in the field that season–or ever again.

Still, one can imagine gun makers overcoming this danger by offering rifles specifically designed to fire Fury cartridges (or confirming that their current models can withstand those pressures). That way, because the external dimensions of a Fury cartridge remain unchanged, hunters could use a souped-up Fury when out in the field while using a less expensive, lower-recoil standard cartridge while at the range.

Handloaders have been able to achieve similar flexibility by loading magnum cartridges to lower pressures for practice and target shooting. But the Hybrid cases allow hunters to achieve magnum performance in small-action cartridges, and they will be able to find both Fury and standard options without having to hand load.

Last Shot

The Hybrid technology isn’t quite perfect–at least not from a consumer perspective. Horner reported that the brass portion of the cases sometimes separated from the steel bases in a resizing die, which will have to be addressed before the product reaches the market.

It also remains to be seen whether hunters will adopt Sig’s new technology. Millions of animals have been taken with conventional cartridges, and the history of souped-up loads is spotty at best.

But hunters, like soldiers and competitive shooters, are always looking for an edge. If a .308 Win. Fury can increase the odds that a 400-yard shot across a canyon will land in the vital zone, you can bet that hunters will at least give it a try.