respectfully, you can't believe everything you read on wiki.
speake wrote quite negatively of baker and other nile source seekers in his journals, some of which i have from gutenberg some years ago. they were in direct competition for grants from various governmental and social providers, and published competing literary works vying for consumption and the riches associated with acclaim and book sales in volume.
Alan Moorehead's White Nile is a great read into the politics of this period in exploration:
https://archive.org/details/in.ernet.dli.2015.536588
i have a first edition that i picked up in a book store some years ago for a buck.
the comment about 16 gauge smooth bore doubles with round ball is from period source references involved in the Zanzibar ivory trade. at that time any ivory was shootable, and any white with a gonne was an "ivory hunter". all you had to do was take a whack at any animal carrying ivory, have some natives track it to death site, and move your camp there for a few days till the tusks loosened and could be pulled out by hand. in the meantime the natives were happy to butcher and market the meat.
Samuel Baker's 2 bore "Baby" was about 40 pounds, and his double 4 was 34 lbs, IIRC. they were muzzle loading curiosities he had made to allow for sensational writing and public appearances, not for carrying. the animals these men faced in the 1840's did not need to be dropped en charge. they were un-hunted and bewildered by their own demise, and did not charge hunters until 1860 or so, according to period reports.