.375 H&H

The .375 Holland and Holland Magnum, often abbreviated as .375 H&H, (Metric Designation: 9.5x72mmB) is a medium bore cartridge introduced by the British company Holland and Holland in 1912. It was the second cartridge to ever feature a belt, which today is a common feature on magnum rounds. Often called "The most useful, all around rifle cartridge".

Origins
The introduction of the 9.3x62mm Mauser in 1905 had a lasting influence on African hunters. The rifles it was chambered for were far cheaper to produce and sell. It could be used on anything, all the way up to elephant. The Mauser action was reliable, and so many military rifles could be re-chambered to take the 9.3. In an effort to stem the tide of this cartridge, several British gunmakers produced their own cartridges to compete. One of these was the .375 Holland and Holland. Holland and Holland determined that it had to have the penetration to take game, and with a bullet of similar dimensions to the 9.3, the penetration was achieved at the minimum of 2150 feet per second. Higher velocity being important, this new round had to have high velocities to penetrate reliably. Higher velocities also means a flat trajectory, so an error in range estimation could be made up for. It also had to operate at low pressures to extract reliably in the harsh environments of India and Africa.

The Road to Popularity
By the time WW1 ended, the cartridge was introduced, and more markets opened in America, as more hunters had a desire to hunt in Africa. The .375 also had a niche to fill in North America, as it could be used on dangerous game there too. Winchester was the first American company to produce these rifles, making them in 1925. After WW2, more gunmakers began to fulfill the needs of the public shooting market as the military contracts ran out. Soon, FN, Winchester, Mauser, and Remington began making high quality bolt actions that spurred the popularity of the .375. When several African countries put bans on using calibers of less than .375 on dangerous game, the obvious solution was to move up to the .375.

Performance
The cartridge was originally developed to use cordite, hence the tapered shape. Modern smokeless powders improve on its ballistics greatly. The velocities of this cartridge are similar to the .30-06, giving it a similar trajectory. Modern loadings give it a muzzle energy of anywhere from 4000 to 4700 ft/bs.