Thanks for the compliments everyone and thanks for fixing the pictures
DD. I'm still rusty at posting pics so I greatly appreciate all the help I can get. This particular cannon was sold before it was completed. When I delivered it to its new owner we decided to fire some golf balls from it to test the recoil system. I had a cheap disposable camera for taking the action photos. Needless to say they didn't turn out. Hopefully I'll hook up with him sometime soon (he's a local guy) and I'll get some good action photos to post .
I used a heavy duty hardware store spring, kinda like a short [12" long] version of a standard garage door spring for the recoil system. The slide moves back about 7 or 8 inches when firing a golf ball with a hot load [700 grains fg] and the carriage moves very little when the slide returns. The entire gun weighs about 130 lbs so that seems to keep the gun stable. The rod on the right side of the gun is the stop which has a rubber bumper. I'll have more info and "how to's" that I'll post shortly. thanks, Dom