Penny, from here west of the Big Pond, I am not sure I understand what you mean by "catapult", with a "slingshot release".
Can you describe the device?

A slingshot in my experience has a Y-shaped handle, the two upper ends bridged (no pun there) with an elastic band (which would have been cut from an automotive inner tube, in my misspent youth). Is that your "catapult"?

Dave Oesterreich