These very large and heavy firearms were the first to be known as the elephant guns of the blackpowder era (1850-1890), though their use also included all thickskinned dangerous game such as Rhinoceros, hippopotamus and cape buffalo. Due to the velocity limitations of blackpowder and lead (usually around 1500 feet per second) the only way to increase penetration was to make a larger gun. The largest bore guns in common use (and bore rifles with the advent of breech loading and rifling in the late 1800's)included the 4 bore- using a 2000 grain (4.57 ounce) slug at up to 1400fps. Despite their enormous power the short low velocity slugs still suffered the penetration issues which plagued guns of this era. Particularly for the toughest shot of all, defeating the bone mass for a frontal brainshot on an elephant. Thus dangerous game hunting in the 1800s was as much a test of the gunbearer's ability to relay guns to the hunter, and his skill on horseback in the earlier days to evade charges long enough to reload. It was not until the parallel developments of jacketed projectiles closely followed by smokeless powders in the late 1800s that dangerous game could be taken with 100% certainty.
Nitro Express Rifles
The Nitro Express line (c.1895), so named because the composition of the early smokeless powders such as axite and cordite is nitrocellulose and nitroglycerin, were the first of the new order of elephant guns. With smaller metal jacketed projectiles ranging from .400 to .620 and velocities around 2000 feet per second they possessed vastly increased trajectory and penetration over their blackpowder forebearers. Within a few short years the mighty bore guns of the previous era largely disappeared from the gamefields. The safari heyday of the early 1900s 'Nitro era' records much literature on such calibres as the .577 Nitro Express, .375 H&H Magnum, .416 Rigby, .404 Jeffery, 505 Gibbs, 450 Nitro Express, .470 Nitro Express and many others. These rifles came out in single shot, bolt action, and double rifle configuration and continued to be used up until ivory hunting died off in the mid 20th century. Thereafter, they largely switched roles to tools for game wardens and as back-up firearms for professional hunters guiding international hunters.
The American gun market produced several famous dangerous game cartridges around this time, such as the .458 Winchester Magnum, .378 Weatherby Magnum and .460 Weatherby Magnum and many of these were 'wildcatted' (to modify an existing case and rifle to fire a different caliber bullet). The rest of the old Nitro express calibers were to fade almost to obscurity until a recent resurgence in safari hunting came about in the 1970s and 1980s. This prompted a new boom in elephant gun development and calibers such as the .416 Weatherby Magnum and .416 Remington Magnum arrived in factory offerings. The late 1980s and 1990s produced the .700 Nitro Express and the new brass manufacturers allowed even more powerful elephant guns such as the .585 Nyati by Ross Seyfried, .577 Tyrannosaur by Colonel Art Alphin and .585 Gehringer by Karl Gehringer to be made by wildcatters. Hundreds more are listed on the Internet's gun forums as the hobby of wildcatting grows. The .600 Overkill made by Rob Garnick represents at this moment the greatest power available from a standard hunting action. Other wildcats based off the heavy machine gun .50 BMG and similar anti-material rounds have been devised which are much more powerful, though they are not generally considered useful hunting arms being that their weight usually exceeds 25lbs.
There is a continuing interest in such firearms especially with the increased hunting opportunities being made for the average wage earner to travel to Africa. Such hunting is relatively expensive though and on a strict licensing system by game departments to allow sustainability of game.