I currently have a S&W 22S .22LR with 5.5 inch heavy barrel. I use it for shooting silhouette and enjoy it quite a bit. I would like to increase my scores though. Would I see better accuracy with a 7 inch barrel or some sort of handgun scope?

I believe that most of us who shoot scoped handguns at metallic silhouettes use rifle scopes on our handguns. We also use barrels 10+ inches in length. and powers 12-24x, Paralax correction to focus targets and target knobs with absolute repeatability. reason being 22lr bullet drop is 8"-9" between 40 and 100 meters. Leopold is very popular but BSA air rifle scopes will get the job accomplishable.