Holland & Holland's early magnum experiment in .30 caliber — a rimmed cartridge on the large H&H case that predated the .300 H&H Magnum by decades. Historically significant as the template from which H&H's iconic belted magnum family evolved.
Type: Rifle
Introduced: 1896, United Kingdom
Parent case: .303 British
Standardization: Obsolete / Non-standard
Bullet diameter: 0.312" (7.92 mm)
Case length: 2.85" (72.39 mm)
Overall length: 3.6" (91.44 mm)
Max pressure: 48,000 PSI
Rim type: Rimmed
Primer: Large Rifle
Typical twist rate: 1:10
Muzzle velocity: 2600–2900 fps
Muzzle energy: 2252–3358 ft-lbs
Effective range: 500 yd
Common bullet weights: 150, 174, 180 gr
Primary use: Hunting, Target
Production status: Obsolete
Also known as: .303 H&H Magnum · Holland & Holland .303 Magnum
History: Holland & Holland introduced the .303 Magnum in 1896 as a high-velocity .30-caliber hunting cartridge on their large rimmed case. The cartridge delivered dramatically higher velocity than the standard .303 British, making it suitable for long-range plains game hunting in Africa and India. It enjoyed a modest following among serious sporting hunters of the Edwardian era. The development of the…
Notable firearms: Holland & Holland bolt-action sporting rifles (custom)
Similar cartridges: .375 H&H Magnum, .300 H&H Magnum, .303 British