.375 Holland & Holland

.375 H&H Magnum
.375 H&H Magnum (Left) with .338 Winchester Magnum (Right) and US Quarter for scale
Type	Rifle
Place of origin	United Kingdom
Production history
Designer	Holland & Holland
Designed	1912
Produced	1912–present
Variants	.375 H&H Ackley Improved, .375 Weatherby Magnum
Specifications
Parent case	Unique
Bullet diameter	.375 in (9.5 mm)
Neck diameter	.404 in (10.3 mm)
Shoulder diameter	.448 in (11.4 mm)
Base diameter	.513 in (13.0 mm)
Rim diameter	.532 in (13.5 mm)
Rim thickness	.050 in (1.3 mm)
Case length	2.850 in (72.4 mm)
Overall length	3.6 in (91 mm)
Case capacity	95.3 gr H2O (6.18 cm3)
Rifling twist	1-12" (304.8 mm)
Primer type	large rifle magnum
Maximum pressure	62,000 psi (430 MPa)
Ballistic performance
Bullet mass/type Velocity Energy 235 gr (15 g) SP 2,895 ft/s (882 m/s) 4,374 ft·lbf (5,930 J) 250 gr (16 g) SP 2,733 ft/s (833 m/s) 4,147 ft·lbf (5,623 J) 270 gr (17 g) FS 2,521 ft/s (768 m/s) 3,811 ft·lbf (5,167 J) 300 gr (19 g) SPBT 2,645 ft/s (806 m/s) 4,661 ft·lbf (6,319 J) 350 gr (23 g) Woodleigh RN 2,325 ft/s (709 m/s) 4,202 ft·lbf (5,697 J)
Source(s): ADI Online Reloading Data [Woodleigh Reloading Book]

The .375 Holland & Holland Magnum (9.5×72mmB) is a medium-bore rifle cartridge. The .375 H&H was only the second cartridge ever to feature a belt, now common among magnum rounds. On these new rimless cartridges the belt replaced the rim in ensuring the correct headspace, which otherwise might be unreliable, given the narrow shoulder of the cartridge case. The British company Holland & Holland introduced the cartridge in 1912 as the .375 Belted Rimless Nitro-Express. It initially used cordite propellant which was made in long strands – hence the tapered shape of this cartridge, which also ensured 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 relatively light bullets in the region of 235 to 270 grains (15 to 17 g), it is a flat-shooting, fairly long-range cartridge ideal for use on light to medium game, whereas with heavy bullets of 300 grains (19 g) and greater, it has the punch necessary for large, thick-skinned dangerous game. In many regions with thick-skinned dangerous game animals, the .375 H&H is seen as the minimum acceptable caliber, and in many places (in Africa, primarily) it is now the legal minimum for hunting such game. African game guides, professional hunters, and cullers of dangerous game have repeatedly voted the .375 H&H as their clear preference for an all-round caliber if they could only have one rifle. A similar preference has been expressed by Alaskan game guides for brown bear and polar bear country

Unlike what is seen in most calibers, many .375 H&H rifles also achieve nearly the same point of impact over a wide range of bullet weights at all commonly used distances, further simplifying a professional hunter's choice in selecting different grain bullets 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.

.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. 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).