Issue with rubber breaking for slingshot crossbow

Hi everyone, ive been wanting to make my own slingshot crossbow for some time, and finally got it working about a month ago, making progressively stronger bands to see how much power i can get, ive been using the tourniquet method for the bands, and this consistently happens after about a week of shooting, these rather large holes appear in the tubular rubber. what methods to you use to secure your bands. Thanks in advance and stay safe.