Well, here is our shooter in its wooden prototype form. It uses a coil spring that would be found on a pickup truck, pulled back about 6 inches I believe for a shooting force somewhere in the area of about 5-600 lbs. In this form we pull it back using a come along, and then release it with a quick release clip.
I was talking to someone on the electronics team and he came up with the idea for a name, The "Aluminum Archer". It's not bad IMO.
https://youtu.be/sWY1oqVhQxk