I'm getting old and can no longer rack the slide on several of my semi autos (Colt officers model and Kahr 380). I've tried all the You Tube techniques without success. I don't really care about the Kahr (replaced by an LCP) but I'd like to shoot the Colt. Obviously I need to improve my hand strength. Any suggestions on what kind of exercises I need to do to accomplish that? Exercise gadgets?