The .375 Holland & Holland Magnum, .375 H&H Magnum for short, is a medium-bore hunting rifle cartridge, designed by British based manufacturer Holland & Holland in 1912. The .375 H&H was one of the earliest cartridges to feature a belt to maximise head space, and has formed the parent case for numerous other cartridges including the .375 Weatherby Magnum and .450 Marlin.
History[edit | edit source]
With the increasing influence of German-made cartridges on hunting rifles, British manufacturers began to develop larger calibre cartridges to hunt big game. Holland & Holland were among the first to release a competing cartridge to the Mauser developed 9.3×62mm that had become one of the most widespread and easy to obtain cartridges in the hunting world. The .375 H&H Magnum was the result of their endeavours.
The .375 H&H was also novel in that it used cordite, and hence produced a relatively low (by modern standards) pressure of 47,000 PSI, which meant that the cartridge could be exctracted with relative ease (ie it would not deform as much as a higher pressure round). Later developments of the cartridge replaced the cordite with more modern powder mixes, with the maximum pressure also increasing.
The First World War and its aftermath prompted Holland & Holland to produce the .375 H&H on a more general basis for the first time, openly selling the cartridge to the general public in 1919. The Second World War, however, was the key to the .375 H&H's continued success, as major manufacturers such as Winchester began focusing on the civilian market. The cartridge of choice for the new wave of hunting rifles: The .375 H&H Magnum.
Design Details[edit | edit source]
The .375 H&H Magnum was designed from the ground up, with Holland & Holland designing a brand-new belted case for their new creation. The overall design of the case was influenced by the choice of cordite as a propellent, which required a tapered casing with shallow shoulder for optimum performance. This aided the extraction of the .375 H&H as it operated more smoothly with the mechanism of the rifle it was used in, a fact that helped to establish its reputation and popularity as a hunting cartridge.
Performance[edit | edit source]
The figures below are based on the performance statistics of .375 H&H Magnum cartridges produced and sold by Hornady.
|Name||Muzzle Velocity (ft/s)||Energy (ft-lbs)|
|250gr 375 GMX® Superformance||2,890||4,636|
|270gr Interlock® SP-RP||2,700||4,370|
|All figures from the Hornady website.|
These figures demonstrate that the .375 H&H Magnum is more powerful than its major rival, the 9.3×62mm Mauser, although the German cartridge is cheaper to obtain. That said, popularity of the .375 H&H has been established by both its performance and reliability through use.
Variants[edit | edit source]
The .375 H&H was produced with a couple of variations of its design, both of which had unique features to change the potential potentcy of the original design.
.375 "Flanged" Magnum[edit | edit source]
The competition version of the .375 H&H Magnum, and originally released alongside the original design. Often used with a 300 grain bullet, the .375 Flanged fires at a lower pressure, but will also take down the largest of game animals as effectively as larger calibres.
.375 H&H Ackley "Improved"[edit | edit source]
A version of the .375 H&H produced by P.O. Ackley, who hoped to improve the power of the standard cartridge. Features a steeper, 40 degree shoulder slope, and is capable of firing a 270gr bullet at 2,830ft/s, a small improvement. Although this cartridge may be used in chambers fitted for the standard round, there is a significant reduction in power as a result, meaning that an Ackley Improved chamber must be used for optimal performance.
.375 Weatherby Magnum[edit | edit source]
Designed by Roy Weatherby in 1944, the .375 Weatherby Magnum essentially features minor modifications to the case design, and was the first cartridge to use the .375 H&H as a parent. The Weatherby is capable of firing at higher pressures, and can achieve muzzle velocities of 2,800ft/s with a 300 gr bullet.
As a parent cartridge[edit | edit source]
The .375 H&H Magnum was used as a basis for a number of other hunting cartridges, particularly the .470 Capstick, .458 Lott, .450 Ackley Magnum, .450 Barnes Supreme, .450 Mashburn Magnum, and the .450 Watts Magnum.