Target Sights kind of tear up one's Holster though...or if one has to draw in a hurry, up comes a bunch of fine Leather 'lint' wadded up behind the front Sight!
If it were me in Brazil in 1916, ".44-40", I would do, absolutely, best choice one could make Calibre wise for South America or Mexico ( back then)...but, I'd have definitely opted for the plain Sights!
What did Percy Fawcett carry, Revolver wise, anyone know?
Siemel also had a Winchester M-92 carbine in .44-40, and the ammo was readily available. I doubt that .44 Special was as commonly found. He never said which sights he had, and probably owned several .44's.
At 38, he married a girl (18) from PA and one of his books shows her with a caiman that she killed with an arrow. Siemel. of course, achieved fame partially through spearing big jaguars.
I know who Percy Fawcett was, and that he was lost in the Amazon, but never saw any mention of the guns that his expedition had. Although British (Siemel was originally a Latvian immigrant to Brazil) I suspect that Fawcett used calibers more available in South America.
I found it interesting in, "King Solomon's Mines" that the author had his men wear Colt's SAA revolvers "of the heavier pattern of cartridge", meaning .45 then. The book came out in 1883, so only .44 was optional. The writer was British, later knighted, but had experience in South Africa and probably chose what he'd have carried on such an expedition. Fawcett was probably also wise enough not to take only UK calibers.
I'm sure that Sir Henry Rider Haggard chose the Colts for ruggedness (by the standards of that day) and for their power. He could as easily chosen .455 or .476 arms, given the locale of his story.
Now that I think about it, I believe that Siemel arrived in Brazil with his brother in 1917. I'll have to get out, "Tigrero!" and see. For a time, he earned a living as an engineer and gunsmith. He seemed especially impressed with S&W's and became a friend of Doug Wesson. He was later given early examples of both .357 and .44 Magnums when they appeared.