If you've seen the Springfield M6 Scout--a .22lr or .22 Hornet over .410--that's a combination gun. The Savage Model 24 is another example that started production in the late 30s and came in a variety of chamberings. Some of the 24s have a built in
Unfortunately, both are out of production, though I guarantee Springfield would sell a truckload of M6s if they brought them back. They can be found on the second hand market at widely varying prices.
I've been doing some looking, and there are a couple variants of the Savage 24 that look especially appealing to the survivor:
- .22lr over 12 & 20 gauge
- .22 magnum over 12 & 20 gauge
- .30-30 over 12 & 20 gauge
- .223 over 12 & 20 gauge
Dave Canterbury has shown a lot of the versatility of the shotgun and ease of reloading in an "extended" scenario on his YouTube channel. The 12 gauge is never going to be a long range gun, though, and the ammunition is difficult to carry in quantity. Pairing a good rifle barrel with that extends your options--you'd have a hunting/foraging gun that could just about do it all.
Anyways, interesting option for hunting and long term post-collapse.
I don't have a 24 and have never personally handled one, so if any of you, my faithful readers have experience with them, let me know. I also may be overlooking other makes/models of combo guns--let me know if that's the case. Would be groovy if there was a current production model of the right flavor.