Holland & Holland introduced the .400 H&H Magnum in 2003 with the intended purpose of hunting large and dangerous game animals. Holland & Holland didn’t make the .400 H&H Magnum cartridge available until 2008 in the United States. The cartridge works in a standard or magnum length action like the .375 H&H but avoids the pressure and heat related problems of the .416 Remington Magnum cartridge. From their reports Holland & Holland has experienced increasing numbers of enquiries for big bore rifles especially for hunting big and dangerous game in Africa. It was also arguably created in response to critiques of the .375 H&H Magnum as not being completely reliable (yet remaining very popular) against dangerous game, particularly elephant in certain conditions.

Holland & Holland designed the cartridge to utilize medium case pressures and intended the cartridge for hot African climates. The .400 H&H Magnum cartridge case possesses slightly tapered shoulders for reliable bolt-action feeding. Holland & Holland also sought to keep muzzle blast and recoil manageable and to negate the need for barrel porting or muzzle brakes. Building on their experience with the peerless all round African hunting cartridge the .375 H&H Magnum they sought to create two new cartridges with more power and provide more leeway for the very largest game. The new cartridges designed for bolt action rifles do not offer light bullets and high velocity instead concentrating on the formula of heavy bullets and bullet diameter to do the job.

Factory trajectory tables computed for a rifle with a telescopic sight mounted 1.5″ over the bore indicate that, with a zero aiming point of 175 yards, the .400 H&H Magnum rifle bullet will deviate no more than 2″ above or below the line of sight from the muzzle to 200 yards. This gives the .400 H&H Magnum a more than adequate maximum point blank range (+/- 2″) of 200 yards. Holland & Holland introduced the larger .465 H&H Magnum, almost simultaneously, with 400 H&H Magnum in 2003. (www.bigbore.org)