Nice thread on the .45 Colt, Long Colt, Government, etc. Always love those. The way I see it, it doesn't much matter as long as you can get your point across without having to have a 2 minute conversation to explain what you mean.
I lost the bubble somewhere, though, in the original question. What exactly is the purpose of the combo? If you've got the SG and the bolt-action in the truck, what again are you doing with the lever and revolver? That makes a big difference in the answer, I think. Why again are you limiting yourself to both weapons taking the same ammo? Was that covered somewhere between page 2 and 6? Need to go back and read those pages.
Great question, I need to go back over some basic thoughts in the OP-
First, this is
NOT a 2 gun long term survival combo. The shotgun and a large bolt gun may not be in the truck, but I have them. Having a family, I have duties far beyond piling guns in a truck and leaving if something really bad happens.
This is intended to look at as a survival combo for short term, emergencies, or unexpected events
while I'm tooling around the outback. But, with that in mind, you have to consider what you'll actually carry and what your purposes are. I like to shoot and will head out into the desert just to do that, which means I don't particularly want to carry a 9 ounce .454 or something. Not a large and heavy bolt gun, unless that's what I'm going out to shoot (but that's not tooling around anymore)
The "same caliber" thing isn't even that- it's a preference for keeping within the same cartridge family. There's a few reasons for this:
1: It doesn't necessarily simplify reloading on all levels, but it does on some. While most of the responses to my reloading focus have been "jarrry Ahern post 500 year apocalypse" - there's also the simple fact that it can be easier to manage reloading
at all times if you don't have to stock 3 different primer sizes, any number of bullet types, etc. You do have to adjust things to load different carts in the same family (like .38 versus .357) though.
2: Versatility. If I'm carrying, say, a .38 revolver and a .357 lever gun (or a .44 special and .44mag lever), it's not the same cartridge, but it's the same family. I can keep a half dozen small game handloads that either will accept, for example. and if something did happen, I would be able to use, with decent effect, the pistol ammo in the carbine should I need to. After all, unless soemthing happens to the carbine, it's going to be more used than the pistol if I have it.
3: And this doesn't directly relate to the "same cartridge family" part, but - I like tooling around out here. lots of variable environmental zones, lots of space. Carrying a handgun is not uncommon or unexpected, carrying a rifle isn't, either. I may not always take the rifle out of the truck, but if I do, I want something that's fairly easy to carry and easy shooting. In general, that gets away from heavier and longer hunting rifles, and for ammunition carrying purposes, away from large bore shotguns. Left with carbine type firearms for a preference, focussing on similar cartridge families between the revolver and carbine makes some sense. Looking at the numbers in the first post, it's also obvious that this isn't necessarily just "shooting a longer pistol", either.
Regarding the lever action itself, Chuck Hawkes wrote somewhere that people often compare the lever gun to the bolt action unfairly. Some bolts actions will have a stronger mechanism, but in general the comparison is unfair because people treat their bolt guns like match rifles and their lever guns as saddle rifles. If you polish and tune a lever gun the same way you do a bolt, you will start getting similar levels of performance.