I don't think i would be using one of these i like to keep my fingers.
http://www.thefirearmblog.com/blog/2013/06/06/single-barreled-ring-cannon/#
and a .50 cal
http://www.thefirearmblog.com/blog/2013/07/08/50-cannon-ring/
http://www.thefirearmblog.com/blog/2013/06/06/single-barreled-ring-cannon/#
and a .50 cal
http://www.thefirearmblog.com/blog/2013/07/08/50-cannon-ring/


















































