I mentioned the .357 Magnum as being an exception to the power equation. This cartridge is very schizophrenic: out of a handgun it has one level of performance, but out of a long gun it changes significantly. The .357 gains a lot of velocity from a longer barrel, to the extent that it almost becomes a different cartridge; it is closer to the performance of traditional rifle rounds than the pistol calibers, but without the former’s recoil and muzzle blast. This makes it very easy to shoot well, and the lever-action carbines in which it is almost exclusively chambered have a simple manual of arms for those who are not firearms enthusiasts. If the carbine is a viable choice, the .357 Magnum is an excellent candidate.
I’ll eventually hit the lotto or find me a sugar mama and get my perfect gun travel kit: Take down lever-action and a revolver in .357 Magnum. Anyway, go on a read Grant Cunningham’s article, it is a damned good one. And subscribe to his blog if you are have not done so.