The Legacy of the Holland & Holland Magnum Chamberings in the Model 70

Among the many legendary cartridges offered in the Winchester Model 70, few match the pedigree of its two original magnum chamberings - the .375 H&H Magnum and the .300 H&H Magnum. Born of British ingenuity and boosted by American market forces, these cartridges have become enduring icons of versatility, power, and reliability.

A Paul Jaeger customized 1949 .375 H&H Magnum Super Grade rifle

Development of the H&H Magnums

The .375 H&H Magnum and .300 H&H Magnum were both developed by Holland & Holland, the renowned London-based gunmaker, famed for their custom double rifles. In the competitive push to capitalize on new smokeless powders at the turn of the 20th century, Holland & Holland presented the world with the .375 H&H Magnum. Introduced in 1912 as the “.375 Belted Rimless Nitro-Express” the .375 H&H Magnum was designed as a versatile big-game cartridge capable of handling everything from African plains game to dangerous animals like lions and Cape buffalo. Its tapered case, gentle shoulder, and moderate pressure made it highly reliable, particularly in the hot climates of Africa and India, where extreme temperature fluctuations often caused issues with other cartridges.

Holland & Holland’s innovation – the belted cartridge.

Groundbreaking in its design, the .375 H&H Magnum cartridge introduced a circumferential belt at the base of the cartridge. This belt, machined into the brass of the case, enabled a precise and reliable means of headspacing the cartridge in the chamber, overcoming the limitations of the .375 H&H Magnum's minimal shoulder. This innovation would subsequently allow the .300 H&H Magnum to be designed with very shallow shoulder angles, resulting in one of the smoothest-feeding cartridges ever made.

The .300 H&H Magnum was introduced by Holland & Holland in 1925 to meet the growing demand for a long-range, flat-shooting cartridge for large game at greater distances. A necked-down .30 caliber version of the .375 H&H Magnum, the .300 H&H Magnum quickly gained popularity among North American hunters pursuing elk, moose and other large, hoofed game. Its impressive velocity and accuracy provided significant advantages over competing cartridges, particularly in situations requiring a flatter trajectory.

Before the innovation of the "belted cartridge," cartridges required either a pronounced shoulder or a widened rim for reliable headspacing, both of which could present feeding challenges in bolt-action rifle designs. The Holland & Holland belted cartridge design resolved these issues, creating a high-powered cartridge that fed reliably in bolt-action rifles. The combination of power, reliability, and smooth chambering made the H&H cartridges instantly popular among hunters facing dangerous game.

Winchester’s Adoption of the H&H Cartridges

Winchester recognized the potential of these British cartridges and became the first U.S. manufacturer to chamber them in a factory rifle, selecting both for the Model 70. The magnum cartridge from Holland & Holland was not a drop-in fit for the Model 70 action, which could not accommodate 3.6-inch-long unfired round. Winchester created the "long-magnum" receiver for rifles chambered in the H&H round by modifying the standard receiver with a longer magazine opening on the bottom, a machined extensions to the ejection port on the top, and a larger bolt face to accommodate the .513-inch cartridge base.

The H&H Magnum chamberings debuted in the 1937 Winchester catalog, with a few rare examples of the model 70 being chambered in .375 H&H Magnum in the 1936 production year.  These earliest model 70s in .375 H&H have come to be known as "pencil barrel" rifles, as they used the standard sporter barrel contour. The large bore combined with the slender standard barrel contour resulted in a very thin-walled barrel. This compromised arrangement was quickly abandoned in favor of a heavier magnum barrel contour which would be used from 1937 through 1963 and made these earliest pencil barrel rifles among the rarest and most collectible of all non-special-order model 70s.

The versatility and performance of the .375 H&H Magnum in the field immediately helped establish the Model 70 as a legitimate option for big-game hunters around the world. Its rise to popularity was boosted by legendary hunter Robert Ruark, author of Horn of the Hunter. As a self-appointed rifle critic, Ruark often sang the praises of the .375 H&H Magnum, even declaring it “the quintessential cartridge for African safaris.” Ruark relied heavily on the .375 H&H Magnum, considering it the perfect balance of power and versatility for hunting everything from kudu to Cape buffalo.

 Winchester rifle and ammunition advertising for the H&H cartridges (1953)

While the .375 H&H captured the imagination of hunters eyeing large, dangerous game in Africa, the .300 H&H Magnum was popular for an entirely different reason.  Its combination of power and accuracy was unrivaled among the .30 caliber cartridges of its day, making it an instant favorite for North American hunters chasing elk, moose, and even grizzlies.

Renowned for its accuracy, the .300 H&H was a hit among match shooters as well, earning its place in competitive shooting history when Ben Comfort used the cartridge to win the prestigious Wimbledon Cup at Camp Perry in 1935. Competing in the 1,000-yard match, Comfort used a custom Griffin & Howe rifle built on a Remington 30-S Express action and chambered in .300 H&H Magnum. The victory highlighted the cartridge’s exceptional accuracy and ballistic performance. This victory not only showcased the long-range capabilities of the .300 H&H Magnum but also helped establish it as a premier choice for precision shooting.

The .300 H&H Magnum would not easily relinquish its reputation or its throne as the world’s most accurate cartridge. Thirty years after Comfort’s Wimbledon Cup victory at Camp Perry, legendary US Marine Corps sniper Carlos “White Feather” Hathcock would repeat Comfort’s feat, winning the 1,000-yard match at Camp Perry and taking home the Wimbledon Cup himself.  Hathcock had competed with a Winchester Model 70 Bull Gun chambered in .300 H&H Magnum.

Ben Comfort and Carlos Hathcock following 1,000-yard victories using the .300 H&H Magnum in 1935 and 1965, respectively.

Legacy and Influence

Holland & Holland’s groundbreaking 1912 'belted magnum' cartridge design spawned a remarkable lineage of high-performance cartridges, all derived from the parent .375 H&H Magnum cartridge. Winchester themselves would develop the full line of Winchester Magnum cartridges from the .375 H&H Magnum parent cartridge. Notable descendants of the .375 H&H Magnum include:

• .300 H&H Magnum (1925)
• .275 H&H Magnum (1925)
• .375 Weatherby Magnum (1944)
• .300 Weatherby Magnum (1944)
• .257 Weatherby Magnum (1944)
• .458 Winchester Magnum (1956)
• .338 Winchester Magnum (1958)
• .264 Winchester Magnum (1958)
• 7mm Remington Magnum (1962)
• .300 Winchester Magnum (1963)
• .458 Lott (1971)
• .416 Remington Magnum (1988)
• .375 Ruger (2007)

The original H&H cartridges on which Winchester based their own magnum cartridge line.

More than a century after Holland & Holland introduced their belted cartridge design, no other magnum cartridge has sired more offspring—14 factory chamberings in all. Its proliferation and enduring success underscores the brilliance of Holland & Holland’s original belted design.

Collector’s Notes

A keen eye will notice subtle differences in the barrel markings of early H&H Magnum rifles. Early models were stamped with generic designations like "300 Magnum" or "375 Magnum," omitting any direct reference to the Holland & Holland brand. Later rifles added "H&H," reflecting the growing popularity of belted magnum cartridges and Winchester’s evolving perspective on its competition.

A 1950 375 H&H Magnum rifle with the abbreviated chambering designation.

By the late 1940s, Roy Weatherby’s wildcat adaptations of H&H Magnum cartridges were gaining traction, prompting Winchester to pursue clearer differentiation in a market increasingly crowded with belted magnums. As Winchester began contemplating development of their own line of magnum cartridges, the need for precise chamber identification became evident. In 1951 and 1952, Winchester updated its chamber markings to include the "H&H." This change not only provided clarity in identifying the correct ammunition but also acknowledged the distinguished British cartridge’s heritage.

Historically, Winchester had avoided spelling out the full names of competitors in chamber designations. Names like Savage and Remington were abbreviated to “SAV” and “REM,” and the Springfield name was avoided altogether, with Winchester opting to use “30 GOV’T 06” to avoid diluting the Winchester brand or promoting a rival. Winchester came to view inclusion of "H&H" brand on their rifles differently, however. Associating a Winchester rifle with the Holland & Holland name was a strategic acknowledgment of the cartridge’s royal pedigree. Unlike domestic competitors, Holland & Holland was seen by Winchester not as a rival but for the prestige of the H&H brand in firearms circles.

For collectors today, the earlier generic "Magnum" markings reflect Winchester’s initial, straightforward marketing strategy. In contrast, the later "H&H Magnum" markings signify a shift toward greater clarity in ammunition identification and an intentional linking with Holland & Holland’s storied legacy.

Modern Magnum Comparisons

Modern magnum cartridges derived from the .404 Jeffery cartridge have grown in popularity since the introduction of the .300 Remington Ultra Mag in 1999.  These newer magnums have a larger powder load and achieve higher pressures, higher velocities and flatter trajectories, for the tradeoff of increased barrel wear and heavier recoil. The larger diameter cartridge also necessitates a large and steeply angled shoulder, which means they cannot match the smooth, reliable feeding of the H&H belted magnum design. And it’s because of these tradeoffs that the original H&H belted magnum design will continue as the magnum design hunters choose most often.

Ballistic comparisons show the remarkable performance of the .300 H&H Magnum, not meaningfully surpassed for nearly a century.

The untarnished reputation of the H&H magnum cartridge for accuracy and reliably smooth feeding will sustain its status as the quintessential dangerous-game cartridge for generations to come. And beyond their performance in the field, the H&H cartridges offer a history and heritage not possible with any modern cartridge. From the storied maker’s name and the nostalgia of more than a century of inclusion on history’s greatest hunts, Holland & Holland’s original engineering will continue to be the magnum design of choice.

Parting Shots

The Holland & Holland magnum chamberings embraced by Winchester for the Model 70, represent more than just powerful cartridges; they embody a rich history of innovative design, competitive success, and the mystique of being so closely tied to the greatest hunts from the golden age of hunting. From African safaris to Wimbledon Cup victories, these cartridges have been perpetually linked to moments of sporting glory. While modern cartridges have managed to eke out marginal ballistic gains, the H&H Magnums maintain a winning combination of ballistics and energy with reliable feeding, manageable recoil, and inherent accuracy. This balance of performance, combined with the rich history and prolific success of these 112-year-old cartridges, ensure their continued relevance among hunters, shooters and collectors for the next hundred years.

A 1950 Winchester Model 70 chambered in .300 H&H Magnum