Well, it’s of the era, certainly , and I have hunted with flints , and yes , it’s a challengeInteresting choice of a rifle. Flint lock, It takes a true huntsman to be able to shoot and control one of those.
but this one is what is called a cartridge conversion
The British took an American design, the Snider system , and modified their pattern 53 enfield rifled muskets to single shot breech loader , firing a massive and slow .577 round
This rifle was used up here in Canada in the 1870s till about 1900
Most notably, the snider was used in large numbers in the US civil war