***Caution: Do not use these adapters in rifle barrels that at semi or full-choke barrels***
In the event you should have access to a shotgun, especially a 12 gauge, single shot breakdown rifle, in your wilderness or urban survival scenario, here is an alternative to carrying light.
There are chamber adapters that modify the chamber of the rifle to accept different size ammo. For instance, there are adapters for 12 gauge shotguns that allow you to fire .22 cal, 9mm, 410, 45 Long Colt, 38 special and 357 cal., and 20 gauge ammo. There are adapters for the 20 gauge and 410 gauge shotguns as well.
Although, you will be limited on the accuracy of shooting at long range targets, being able to shoot multiple size ammo will allow you more flexibility in a survival scenario.
You can make a pouch to attach to the stock of the rifle to carry the different size adapters that you want to use.
I have noticed that when shooting the different sized ammo, the rounds will tumble down range rather than spiral when being shot out of their prospective weapon systems.
I present this as another opportunity or idea that will help prepare you to better survive in a scenario that may require the need for something like this. It is light weight and cost effective if you can not afford the different size weapons.
Stay Prepared! Stay Alive!