[mauvehaus]

If you live in a more rural area, a gun with ammunition can be a viable source of food. The shelf life of ammunition is a squishy subject, but with good storage it's reasonable to expect it to last on the order of a human lifespan.

Absent a complete ecosystem breakdown, game feeds itself. Obviously if too many people are hunting, there's the risk of killing off all of the game. Which is another excellent reason that is would be a strategy better suited to a less populated area.

It's hard to imagine a more efficient way (measured in money and space required) to supply food for potentially decades.