Re: Historical inquiry/identification
We can't even say it is percussion; at that time it would probably have been a flintlock. But the others are right, it is just an artist's rendition of a gun. It is not intended to be an accurate drawing of a real gun any more than the "rifles" in the Beetle Bailey cartoons are intended to look like those actually used by the army.
At the time, I am sure the cartoonist's intent was to show the noble white man triumphing over the evil and bloodthirsty black leader of a slave revolt. A more modern caption might be, "Don't bring a short sword to a gunfight."