minimalistic slingshot

I designed a small, minimalistic slingshot for my kids. It's supposed to be used with rubber bands I bought on Aliexpress. The inner diameter of the rubber bands are 6mm. The bands stay in place with the help of 2 tie wraps. It's been shooting for days here without coming loose. this is the link for the rubber bands: https://a.aliexpress.com/_EvPguMQ My kids and myself ONLY shoot at non living targets!