Choosing a rifle calibre
The term calibre refers to the diameter of the bullet and the corresponding hole through the rifle barrel.
For example, calibre 7.62x51mm, means the bullet is 7.62mm in diameter, and the diameter of the grooves in the barrel is 7.62mm. The second number refers to the length of the brass case the bullet is seated in in this case 51mm.
We may have a similar size bullet, however differing size cases, for example the .30-06 (7.62x63mm) and the .308 (7.62x51mm) both shots are similar, however the second .30-06 has a longer case.
Choosing a calibre depends on what you intend to hunt, small game, large game, or target shooting. Many calibre of rifle can be used for mixed uses - the .308 Winchester is popular for both hunting and target shooting. However some rifle calibre are more specific, for example a .204 Ruger is used for small pest control, popular for fox hunting in the UK.
When we come to the energy of the bullet, increasing speed has a greater impact than increasing weight - doubling the weight only doubles the energy of the impact, however doubling the speed increases the energy by a factor of four.
Read more on choosing a rifle.
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Below is a list of popular hunting, and other well know rifle calibres.
Rifle by Caliber
.50 BMG :
The .50 calibre Browning Machine Gun (12.7x99mm) was designed by John Browning during WWI as an anti-aircraft weapon - a scaled-up .30-06 round. The .50 cal heavy machine was designated the Browning 'M2', and still is used all over the world by airborne, armoured and ground troops.
The .50 BMG is also widely used in bolt-action and semi-automatic sniper and target rifles. The velocity of a 700 grain bullet is 3,000 FPS (feet per second) generating 14,000 foot pounds energy.
.416 Barrett :
The .416 Barrett was designed in 2005 by Pete Forras, as an alternative to the .50 BMG in large long-range rifles. It was designed to provide a medium to heavy rifle and cartridge combination for the Naval Surface Warfare Centre, Crane Division, in late 2004.
The cartridge fires a CNC-machined solid brass bullet designed to have low supersonic drag, resulting in ultra efficient bullets, traveling at 3,250 FPS for over 2,500 yards. The .416 Barrett usually fires a 400 grain bullet at 3,250 FPS generating 9,400 foot pounds energy.
.408 CheyTac :
The .408 CheyTac 'Cheyenne Tactical' was developed by Dr. John D. Taylor and William O. Wordman to fill the gap between the .338 Lapua Magnum and the .50BMG. It was designed as a anti-personnel, anti-sniper and anti-materiel bullet.
The .408 CheyTac is unusual, because it is made from a copper-nickel alloy rather than the common copper jacketed lead.
Due to the metal construction and the unique precision turned design, the bullets have a tremendously high ballistic co-efficient of 0.934 and the 419 grain projectile remains supersonic in flight to over 2,200 yards. The .408 CheyTac usually fires a 419 grain projectile at 3,000 FPS generating 8,400 foot pounds energy.
.416 Rigby :
The .416 Rigby (10.6x74mm) was designed in 1911 by John Rigby & Company of London for dangerous game hunting in Africa - the first rifle to use a bullet with a .416 diameter.
The cartridge case is one of the largest ever designed for a bolt-action rifle, at the time cartridge were loaded with Cordite, that burnt very hot causing in increased in chamber pressure, often resulting in jammed cases. The large case and relatively low pressure made the .416 Rigby solved this problem. This was a great benefit, especially when being charged by one of the dangerous games.
Even today the .416 Rigby is still a popular big game cartridge for Africa game hunting and, even in hunting in the USA. The .416 Rigby usually fires a 400 grain bullet at 2,400 FPS generating 5,100 foot pounds energy.
.338 Lapua Magnum :
The .338 Lapua Magnum (8.58x70mm) made by Lapua of Finland in partnetship with Accuracy International of the UK as an anti-personnel and anti-materiel sniper round, and is commonly used in the Iraq and Afghanistan conflicts.
When used for hunting, it is quite capable of taking down any animal, however African countries specify .375 cal as a minimum for some game.
The .338 Lap Mag usually fires a 250 grain bullet at 3,000 FPS generating 4,900 foot pounds energy
.375 Ruger :
The .375 Ruger (9.5x65.5mm) was a collaboration between Hornady and Sturm Ruger. Their aim was to create a cartridge with the performance of the .375 H&H, in a package better suited to modern rifles.
The case shorter than a .30-06 case, therefore a long action receivers can accommodate this cartridge. The Ruger case holds a few more grains of powder than the H&Hs, therefore is able to match the .375 H&H performance, with the wide, minimally tapering case giving extremely efficient powder combustion. Even with shorter barrels, the Ruger cartridge is 200 FPS faster with lighter 250-270 bullets and around 100 FPS faster with the heavier 300 grain bullets.
As the .375 Ruger cartridge fits into smaller lighter rifles than the other large dangerous animal cartridges, such as the.375 H&H, this results in an increase it the perceived recoil . .375 Ruger usually fires a 270 grain bullet at 2,750 FPS generating 4,400 foot pounds energy..
375 H&H Magnum :
The .375 Holland and Holland Magnum is one of the classic hunting cartridge. Introduced by Holland and Holland of the UK in 1912 it was originally called the .375 Belted Rimless Nitro-Express.
With a light 235-270 grain bullet, it is perfect for light up to medium sized animals, for larger game, go for a heavier 300 grain bullet. In a lot of Africa the .375 H&H is the legal minimum caliber when hunting the dangerous game animals, and is the favourite all round hunting caliber for African professional hunters.
The .375 usually fires a 270 grain bullet at 2,700 FPS generating 4,350 foot pounds energy.
.300 Winchester Short Magnum :
Also known as the .300 Whizzum, the .300 Winchester Short Magnum was introduced in 2001 by Winchester. It was based on the .300 Winchester Magnum, with the design shortened, aiding shorter stiffer actions, thus allowing greater accuracy of the rifle.
The .300 Winchester Short Magnum usually has a 165 grain bullet at 3,200 FPS giving 3,800 foot pounds energy.
9.3x74R Ruger:
The 9.3x74R was invented in Germany around the 1900, designed to be used in double- rifle and single shot non-bolt-action rifles. The 9.3x74R is still popular in Europe for wild boar driven hunts or stalking.
It was initially designed for the large European game including moose and brown bear, however dangerous game hunters would also take it to Africa with them, and still remains a popular rifle in African safaris.
The 9.3x74R usually fires a 286 grain bullet at 2,350 FPS generating 3,500 foot pounds energy.
.300 Remington SAUM :
The .300 Remington Short Action Ultra Magnum, was released in 2001, to compete with the .300 Whizzum, following trends for shorter, fatter cases. The .300 Remington SAUM usually fires a 180 grain bullet at 2,950 FPS generating 3,500 foot pounds energy.
.300 Winchester Magnum :
The .300 Winchester Magnum (7.62x67mm) was introduced in 1963 as part of the Magnum range, for shooting large game and long range targets. Due to its long range ability, it has been adopted by both law enforcement, and military snipers in the past. It usually fires a 180 grain bullet at 2,950 FPS generating 3,450 foot pounds energy.
7mm Winchester Short Magnum :
The 7mm Winchester Short Magnum (Whizzum) was designed by Winchester and the Browning Arms Company in 2001. It was based on the .300 Whizzum, reduced to take 0.284" bullets. The 7mm Whizzum is ideal for hunting of larger game including bear, elk, or deer.
The 7mm is a great compromise between the 6.5mm and .30 calibre bullets traditionally used for long distance target shooting. The 7mm Whizzum usually fires a 140 grain bullet at 3,200 FPS generating 3,200 foot pounds energy.
.30-06 Springfield :
The .30-06 (7.62x63mm) is a .30 calibre round, designed by the US Military in 1906. and was mainly a military cartridge, seeing action in both rifles and machine guns up to the 1970s when it was replaced by the 7.62x51mm.
Today, it is the most common hunting cartridge in North America, usually firing bullets weighing 150-180 grains at velocities of around 2,850 FPS generating 2,800-3,300 foot pounds energy.