The .375 H&H Magnum, also known as .375 Holland & Holland Magnum, is a medium-bore rifle cartridge introduced in 1912 by London based gunmaker Holland & Holland. The .375 H&H cartridge featured a belt to ensure the correct headspace, which otherwise might be unreliable, given the narrow shoulder of the cartridge case. The cartridge was designed to use cordite which was made in long strands – hence the tapered shape of the case, which, as a beneficial side effect also helped in smooth chambering and extraction from a rifle's breech.
The .375 H&H often is cited as one of the most useful all-round rifle cartridges, especially in shooting large and dangerous game. With bullet weights ranging from 235 grains (17 g) to 350 grains (23 g), it has the necessary punch for small to medium game, as well as large, thick-skinned dangerous game. The most common bullet weight available in this caliber is 300 grains (19 g). In many regions with thick-skinned dangerous game animals, the .375 H&H is seen as the minimum acceptable caliber, and in many places (primarily in Africa) it is now the legal minimum for hunting such game. African game guides, professional hunters, and dangerous game cullers have repeatedly voted the .375 H&H as their clear preference for an all-round caliber if they could have only one rifle. Alaskan game guides have expressed a similar preference for brown bear and polar bear country.
Unlike many other calibers, .375 H&H Magnum rifles achieve nearly the same point of impact over a wide range of bullet weights at all commonly used distances. This simplifies a hunter's choice in selecting different bullet weights, based upon the game hunted, by requiring fewer scope or sight adjustments, which further serves to popularize the .375 H&H Magnum among professional hunters.
History and origins
The .375 H&H Magnum is the result of competition between British rifle manufacturers to develop new cartridges to take advantage of the new smokeless powders. The 9.5×57mm Mannlicher–Schönauer cartridge had a major influence on British rifle manufacturers and was soon adopted by Westley Richards and Eley as the .375 Rimless Nitro Express 2.25". In an effort to compete, Holland & Holland introduced the .400/375 Belted Nitro Express.
.400/375 Belted Nitro Express was developed in 1905 and the 9.5×57mm MS – just in 1908.
The .400/375 H&H (also known as the .375 Velopex) as it is sometimes known was the first cartridge manufactured to feature a belt. The addition of a belt to a rimless cartridge design provided the advantage of allowing for correct headspacing of highly tapered cartridges (an advantage of flanged cartridges) and smooth feeding through magazine rifles (the advantage of rimless cartridges).
The introduction of the 9.3×62mm Mauser cartridge in 1905 had a profound and lasting influence on hunters in Africa. Compared to the British double rifles, the Mauser was a far less expensive rifle to manufacture and therefore cheaper to acquire. The double rifles gained little from industrialization whereas the Mauser rifles had gained from mass production due to contracts to produce military rifles for many countries. The result was cheap magazine rifles capable of firing one of the very best candidates for the all round hunting cartridge in Africa. The influence of Mauser's 98 action should not be understated; British gunmakers such as Rigby were purchasing the Mauser 98 actions for use in their own rifles with their own cartridges. The popularity of the 9.3×62mm Mauser was such that everyone from the German farmers in Africa to the white hunters from Europe discarded their previous doubles and less powerful magazine rifles and took to the 9.3×62mm. The 9.3×62mm demonstrated that it was adequate for everything from the dik-dik to the elephant and had acquired a reputation to match.
This trend did not go unnoticed by British rifle manufacturers. Between 1909 and 1911 Holland & Holland, Jeffery, Rigby, and Westley Richards introduced their own cartridges: .375 H&H Magnum, .404 Jeffery, .416 Rigby, and the .425 Westley Richards in an effort to stem the tide of the 9.3×62mm.