I considered a ML, too; we have experimented with chert as the rock in a flintlock and got fire, but realistically, loading cases with smokeless is far more efficient, the primers are WAY cheaper than caps for a caplock , and ya have to mould R-Balls as well as conicals for a fixed ammo gun, so thats a tossup.
The tip-up shotgun is the 'modern' version of the NW Trade Gun type, and a good replacement it is, too.
As an old muzzleloading (is that redundant?) guy I want to believe they are still the thing, but, for other than sport, anybody in the bush with one would trade his (pick fav. whatever) for our breechloaders (though he would keep that ML in reserve).
Best is sooooo relative....
Most of us, in a survival sense, would be better served knowing how to make half a doz. snares and run the trapline everyday, if we want to eat regularly. There are a lot of daily tasks that take time away from hunting for the pot that it gets too iffy to spot and bag game. In travel, it is a meal of opportunity, of course, but slow enough travel to be still hunting is low mileage.
Even so, boys do like to carry guns, dont we?