One very practical approach is to carry a medium power longarm and complementary sidearm. For example, a favorite pair I carry on deer hunting trips is a bolt action .30-06 rifle and a .22 LR revolver, normally a S & W 63 kit gun. Such a readily portable battery has sufficient power for anything in North America, albeit a little light for grizzlies. OTOH, it also deftly covers small game hunting. Such a pairing of complementary guns allows great breadth of coverage with normal full power loads which are so readily available.

Some other broad complementary pairs would include a sidearm and a combination gun which provides both a rifle and a shotgun barrel with one superimposed over the other. In addition to the previously mentioned Springfield M6, the Savage M24, and a Russian import under the name Baikal make available shotguns in 12 and 20 ga., and .410. They also cover the gamut of calibers from .22 LR through .30-06 and beyond. If for instance the Savage 24 is chosen with .22LR and 20 ga. 3" magnum, then a good complement would be a medium to high powered handgun. An alternative longarm would include a dedicated rifle in .22LR or even a shotgun.

Another obvious consideration in choosing a survival gun is the weight of ammunition. In preparation for various activities, we recorded the following weights of factory ammunition in factory boxes (as weighed on our somewhat aged baby scale, YMMV):

.22 LR--5oz.--for a box of 50 rounds of 37 gr. hollow points.
.32 H & R Mag--17.5 oz.--50 rds., 95 gr. bullet.
.357 Mag-- 30 oz.--50 rds., 158 gr. bullet
.44 Mag--59 oz.--50 rds., 240 gr. bullet.

.223 Rem--8 oz.--20 rds., 55 gr. bullet.
.243 Win--14 oz.--20 rds., 100 gr. bullet.
.270 Win--17 oz.--20 rds., 130 gr. bullet.
.30-06 Spr--19 oz.--20 rds. 150 gr. bullet.

20 ga--35 oz.--25 rds., 1 oz. shot.
12 ga--45 oz.-- 25 rds., 1 1/4 shot.

John