The bandsaw has been mentioned here and it is fine if it is good enough quality and you know how to handle it. Either one of those conditions prevented me from using one to any advantage. My father gave me a hand rip saw a few years before he died, precisely because I had started to build muzzleloaders from planks of wood. I had my own crosscut handsaws and was very good with them. I found that, while it was a lot of very good upper body exercise, I could precisely saw out the profile. Then I could saw away the extra wood on the sides of the barrel, lock panels, etc. It was not as much work as you might think. And the potential for disaster is much less with the handsaw. When I needed to start shaping, with the barrel, lock and triggers in, I used the spokeshave, the chisel and the gouge for removing and rounding the wood. I didn't use the rasp much because: a, it was slow, and b, it left gouges in the wood that went deeper than you realize and sometimes didn't show up until I stained the wood. I found that I could get very close to the final shape with the chisel and gouge. I used a course file for some clean up before sanding or scraping. I only scraped the last one I built and wish that I had tried it much earlier, because it is so effective and such a pleasure to do.
Just my humble offering of another method. I did it because it worked for me, not because of any desire to be historically correct in my methods.
volatpluvia