How can I make objects stay in the basket of my slingshot?

How about thoroughly wetting it, forming it around a ball or rock until it dries in that shape. Wrap it with enough layers of twine to get it to stay that way while drying, if necessary.

I thought you held it in with your fingers and then released everything together. I don’t understand what you mean???

Are you pinching the leather with the projectile in place? You should feel the object through the leather. Make sure it is in line with the rubber and attachment holes.

@rooeytoo, @LuckyGuy I think that the OP is referring to a slingshot of a different sort.

The first line of your link says “Not to be confused with slingshot.” I have heard the ones you link to called Sheep herders sling. If that is what the op means, then that is a horse of a different color for sure!

@luckyguy yeah I just realized that lol! I had a string tied on the basket of it to pull it back and make things easier but no it just doesn’t work like that.