Okay, it is my understanding that in the hiarchy of human survival, food is pretty low on the totem pole.
You can bleed to death in seconds, so stopping major bleeding is first.
Air, you got minutes only there, so that is second
Shelter vs Water, you can go a few days without water, but it really makes doing anything else really difficult. Dehydration will as quicky start to affect your ability to reason (after 12 hours or so). But then, if you are lost, and are just going to stay put, then not a whole lot of thinking involved (until you dehydrate and then think it is a good idea to go look for water). Shelter, exposure to the elements can kill you in a single night in the spring/fall in the right conditions, in the winter, in just a few hours you can die.
Food, well, you are going to be just fine for a week, probably 3. Anyways, by day 4 you will probably be eating bugs so no big deal.
Hence, harvesting food, should that be the primary goal on which to design a survival rifle?
What about signaling with it? what about defense? (because being lost in the woods is only one type of survial situation) Honestly, weight wise, would you be better off with a .22 LR plus 100 rounds for getting food, or a single shot 410 and 10 flare rounds?