Hey NiceRack! Welcome to the board! Always remember one thing, there are no stupid questions, just stupid answers. I have lived in Missouri all of my life. My suggestion to you is to contact the Missouri Department of Conservation for the answers to alot of your questions about the outdoors. Missouri has a top notch fish and game department and I have never had any trouble obtaining information from them. To answer your question as a few others already have. No, it is not legal to hunt deer by way of a slingshot in this state. However, I did some checking on what COULD be taken in this state with a slingshot, and BESIDES deer and turkey, you may use a slingshot during the prescribed hunting seasons.(see page 76 of the Wildlife Code of Missouri, 2002) I remember years ago, my father and grandfather using slingshot for the exact same reason as stated by Halcon earlier. Don't be afraid to ask questions about the sport here, there will always be someone to help you sort through the B.S.. Good luck!!