Few hunters will ever truly need a big bore cartridge, but when you need one, you reallyneed one in the worst way possible. After all, sometimes bigger really is better.
However, since most of the biggest rifle cartridges were primarily used in the specialized role of stopping a charging buffalo or elephant at short range, relatively few hunters have ever shot, much less owned a big bore rifle.
Even so, there is a certain mystique about them. Perhaps that stems from a fascination many have with hunting Africa around the turn of the century. It may also just have something to do with the allure of owning or shooting the biggest possible rifle.
Regardless of exactly why some people love them so much, certain big bore rifle cartridges have really made a significant impact on the hunting world.
Before we get started, keep in mind that this is not meant to be an exhaustive list of really big rifle calibers. Instead, this article is primarily focused on the big bore hunting cartridges with outsized roles in hunting lore or cartridge development. For that reason, it does not include some more modern cartridges like the .577 Tyrannosaur and .600 Overkill or one-off novelty cartridges like the .950 JDJ.

.577 Nitro Express

.577 Nitro Compared to .22 CB. (Image: Wikimedia)

With the development of smokeless propellants in the late 1800s, British manufacturers wasted little time in developing what became known as the “Nitro Express” line of cartridges.
Born by adapting the old .577 Black Powder Express cartridge to use cordite, the new .577 Nitro Express 3″ cartridge was a dramatic improvement in performance over the old black powder load. It fired a 750-grain bullet at 2,050 feet per second for an astounding 7,000 foot pounds of energy.
This huge cartridge quickly developed a reputation for incredible stopping power and was extremely popular among elephant hunters around the turn of the century.

.600 Nitro Express

.505 Gibbs, .600 Nitro Express, 9.3x62mm Mauser, .308 Winchester. (Image: Big Game Hunting Adventures)

Not content with the performance of the .577 Nitro Express, W.J. Jeffery & Company developed the .600 Nitro Express cartridge a few years later. Firing a 900-grain bullet at a velocity of 1,950 feet per second with an incredible 7,600 foot pounds of energy, the .600 Nitro Express was the most powerful hunting cartridge in the world for the better part of a century.
Like the .577 Nitro, the .600 Nitro Express excelled in its primary role of stopping elephant and buffalo charges at close range.

.700 Nitro Express

.700 Nitro Express. (Image: Pinterest)

The .700 Nitro Express is the oddball cartridge on this list. It was not part of the original Nitro Express line and was instead designed by American shooters Jim Bell and William Feldstein.
As the story goes, Holland & Holland had completed production of their .600 Nitro Express series of rifles and refused to build Feldstein a new rifle in .600 Nitro. So, Feldstein and Bell designed what would become the .700 Nitro and asked Holland & Holland to build him a rifle chambered in that cartridge instead.
Holland & Holland agreed, and the new cartridge ended up sparking enough interest that the company started producing rifles chambered in .700 Nitro and even restarted production of rifles chambered in the .600 Nitro cartridge as well.
Firing a 1,000-grain bullet at 2,000 feet per second, the .700 Nitro Express packs a wallop with 8,900 foot pounds of energy. After it came on stage, the .700 Nitro took the title of the most powerful hunting cartridge sold commercially from the .600 Nitro.

4 Bore and 8 Bore

.600 Nitro, .577 Nitro, .30-06 Springfield, 8 Bore, 4 Bore. (Image: Rifle Magazine)

Now we need to go way back in time to the early days of European settlement in Africa to discuss the next entries on the list. Before the advent of smokeless powder and good quality jacketed bullets, hunters had to resort to shooting massive lead projectiles to have any hope of taking down the enormous game they encountered in Africa.
These massive firearms were the first elephant guns, and their size was denoted in the old English manner of bore or gauge (like a shotgun) instead of caliber. While hunters also used 2, 6 and 10 bore guns on occasion, the 4 bore was probably the most popular for hunting elephant, and the 8 bore was most popular for animals like buffalo and hippo.
Though there was some variation in the exact projectile sizes, an 8 bore rifle normally fired a humongous .835″ projectile, and a 4-bore fired a projectile around 1″ in diameter. These guns originally began as muzzleloaders and eventually were developed into breechloaders that used fixed cartridges.
For that reason, there was quite a bit of variation in loads for the 4 and 8 bore. A common 8 bore load was a 2 ounce (875 grains) round ball fired at muzzle velocity of about 1,600 feet per second. One popular 4 bore fired a 4 ounce (1,750 grains) projectile at around 1,500 feet per second.

For many years, these guns were the most effective means of taking down big animals like elephants. However, they had tremendous recoil and were incredibly heavy, and those gigantic lead projectiles did not penetrate well. Not surprisingly, the 4 and 8 Bore were quickly eclipsed by the Nitro Express cartridges that came along in the late 1800s.