I shoot slingshots for fun, not hunting. But they are very good for hunting small game a close range. Provided you have practiced and become proficient. You will not pick up a slingshot, never having used on before, and start harvesting yourself rabbits on your first attempt. You'd be hard pressed to hit a cow from 15 feet away! So, practice is your first order of business. It takes a while, but not too bad.

You will need spare bands. Don't hold out false hope that you can steal the elastic from your underwear or bra to power your slingshot in an emergency. Bands die from use (obviously) but they also die from UV radiation. So keep them stored in dark containers. Inspect frequently for signs of wear. The smallest crack/nick on a band will cause it to fail very quickly.

Remember your safety glasses (or at least regular glasses or sunglasses at a minimum)! Many people don't understand that when a slingshot band breaks it is at one of two places. Where it attaches to the pouch (which will most likely be a "harmless" break - whacking your hand/arm possibly), or where the band attaches to the fork. If it breaks at this second place, you have a broken band flying right back at the eyeball you are aiming with. That is not an injury you ever what to have, let alone in a survival situation. In addition to safety glasses, before drawing the band and raising the slingshot up in front of your face (this is the way most, but not all, people shoot), inspect the bands closely for damage and then stretch them a couple of times - away from your face! - so that if they are just about to break it won't be in front of your eye on your first shot.