The Webley Mark 3 has much to recommend it: good damage, and rapid fire. The Smith and Wesson 'Russian' revolver is slightly more powerful, but is alas not 'double action' and so cannot be fired rapidly without careful training. Both can be loaded quickly. The possession of a Remington 'Double Derringer' hidden about one's person might also be recommended, particularly to the fair sex.
Persons of even slight stature might find the Winchester Model 1876 in 45-75 Winchester calibre a useful tool against any but the largest opponents; its magazine holds 8 cartridges. The Royal Canadian Mounted Police certainly find them useful in 'getting their man'! The Winchester Model 1886 is also useful, and is slightly more accurate -- and expensive.
Among the bolt-action rifles, the Remington-Lee Sporter might be considered for being both hard-hitting and easily-reloaded: the manufacturer offers additional five round detachable magazines at a cost of a few shillings each; these might be carried about in a pouch by the gunner, to be quickly exchanged with the empty magazine in the weapon. The adventurer choosing the Mauser Gewehr 1888, also known as the 'Kommission-Gewehr', cannot fail to be pleased by its accuracy, power, and speed of reloading (using en bloc clips, which are simply pushed into the action along with the five rounds which they contain).
For heavy game, the heaviest double or cape gun that can be managed by the adventurer is recommended. If of small stature, or female, a German Drilling or Vierling might be useful ... their increased weight tames the recoil somewhat, of course at the effort of carrying them about.
The use of 'howdah' pistols is most often sadly necessary when other firearms have failed, by want of accuracy skill cartridges or power, to bring down some onrushing beast intent on viewing and possibly digesting an adventurers most private and vital organs. Except for the Lancaster Howdah in .577 Boxer calibre, few persons can effectively wield these weapons.
The Winchester Model 1887 lever-action shotgun has at least the advantage of holding five shotshells in a magazine tube beneath the barrel; it cannot unfortunately withstand the stress of firing the powerful new smokeless shells, and must use only black powder rounds.1889 Index Page