The cowboys of the Old West used to carry a rifle and a pistol chambered for the same round. That still makes sense today if you plan on packing your firearms and ammo around in a SHTF scenario. For that reason many folks have a rifle and a handgun both chambered in very available .357 mag.
Best all-around weapons system for SHTF remains the AR-15 in 5.56 or .308 in combination with a good handgun IMO. While .22’s are great, if my life depended on the outcome of a firefight or dropping a pig or deer for food, I want America’s battle rifle in my hands.
The popular combo in the 1870s and '80s was the 44-40 black powder cartridge chambered for both the 1873 Winchester (the real gun that won the West not the 30-30) and Colt revolver.
7.62 x 25mm..can do the same.
I have a slightly different perspective. It takes a long time and effort to prepare and preserve a deer or a pig. A lot of the time, I'd rather just shoot a single meal (duck/squirrel/rabbit) and cook it immediately, and squirrels are as common as rats but easier to find. For single meals, I'll take a .22 so long as I'm not limited to that single caliber.