I have several rifles with no standing rear sight, a Jean van Maele double in .450/400 3 1/4, Westley Rchards Monkeytail sporter
(with 6 standing leaves and upright slider without the usual standing sight), a .577 Kerr sporting Snider as well as the obvious Paradox

I have unfortunately not hunted with any of them, but the feel most peculiar on first sight

TH44