I'm aware of the scene (at least from the TV show) that you're referring to. I was asked by a customer when I picked up my fowler "how many shots can you fire a minute?", as he picked up his new bolt action, I just smiled and said "maybe one!". The shop owner did come to my defence and pointed out that I'd recently shot buffalo with a muzzleloader, I think the other fella was a bit surprised and couldn't think of another tongue in cheek comment to make after that!
The scene I'm referring to in the revenant is shot not ball, you can hear as he's spitting it into the bore lots of little pellets trickling down the bore.
For all its faults I do like that in several scenes of the movie the Patriot, there is pan priming.