Another "new" survival type gun is the Chiappa M6 X-Caliber (based on a similar Springfield M6 Scout aircrew survival gun that is out of production).
Folding over-under 12 ga and .22, add the adapter kit for multiple caliber versatility. In addition to the two original gauges, adapters allow you to shoot 8 pistol calibers ( .380 , 9 mm , .357 Mag/.38 SP , .40 S & W, .44 Mag, .45 ACP , .410/.45 colt ) and two shotgun calibers (410 ga and 20 ga), combining the flexibility of a shotgun and the power of a rifled gun.
http://www.chiappafirearms.com/product/2673
View attachment 6836
View attachment 6837
View attachment 6838
View attachment 6839