Most of the old camping text, those of a century or so ago, list good and varied recipes for pemmican. This is particularly true of the northern American texts, as pemmican is generally a food of the north woods and colder climes. A more modern recipe can be found in "The Winter Wilderness Companion" by Garrett and Alexandra Conover:
"Recipe fills four 12-oz. tuna cans.
Melt together:
2 cups animal fat
1 cup bacon drippings
Pour over:
2 cups finely ground dried meat (jerky)
Sprinkle with salt, pepper. Let harden in tuna cans with lids removed. Loosen pemmican by dipping cans partway into hot water. Wrap in waxed paper. NOTE: Dried berries (2 cups) can be added for carbohydrate content and extra flavoring. However, a true pemmican contains only fat and meat."
I'd suggest avoiding commercially produced jerky if at all possible. Make your own, or find someone who makes it with no additives. One vital part of pemmican is not in the recipe: it should be eaten with plenty of water, because digesting all that fat is hard work and takes a lot of fluid.
Storage time is naturally variable, and of course temperature and the container used make a difference, but I've heard of good pemmican typically lasting for years. In freezing conditions the stuff will probably outlast all of us. In one of his programmes I recall Ray Mears sharing Vietnam war-era pemmican with an American survival instructor...