......Also, depending on what you are looking to hunt, I would have thought that the weight of black powder and a heavy lead ball, is going to be a poor food vs weight ratio, compared with modern centre fire ammunition. Coupled with the reliability issues and the problems of damp/ spillage of carrying a flintlock loaded whilst stalking...
I would have thought that in pure survival terms something like a 223rem would be a better choice. (Pack a chamber insert for 22lr and you have the best of both worlds.)
I don't think many of us would disagree that modern cartridges and arms for them are better. I certainly thing the modern one are better; in terms of both ballistics and convenience/ease. That said, most of us arguing for blackpowder and arms (apart from the OP perhaps)are doing so from the belief that the older arms and ammo are more than sufficient.
Lead balls are actually pretty light. A sphere has a small volume compared to a cylinder.
A .45" musket ball, for example, weighs about 138grains. That's a smallish musket ball.
Blackpowder is tiny in weight compared to anything else you are carrying. A pound of black powder is a lot of shots.
I still think that for long-term survival, a crossbow would be better.
Agreed on all points. In arguing the relative effectiveness of a crossbow (or even and ordinary bow) compared with a muzzleloader it's interesting to note that Indigenous peoples armed with the bows won more than one fight against the Europeans.
The only caveat would be that you have the skills to make new bolts and broadheads.