Thank you for all of your input and points.
A few years back, I had to shoot my old 16ga Savage M940 single shot quite a bit over several weeks, trying to get it sighted in. It hurt, but not for long.
As a kid, I never remember my father sighting in our shotguns before the season (Western NY, slug only). Never understood why I missed so many deer as a kid. It had a full choke which didn't help but then even after having it bored out to improved cylinder it didn't shoot.
Late 80's I missed a kneeling, broad side 45 yard shot at a big VA 6 pointer. After I became a LEO, finally got some range time with it and discovered it shot 24" low and 18" left at 50 yards. A machinist who worked for me clamped the chamber end into his biggest lathe. You should have seen how the muzzle end orbited. He started whacking on the muzzle end with a 5 pound plastic mallet until it was true. He said where he grew up in GA his Fathers buddies would put the end of their single shots shotguns in a crook of a tree and flex them until they shot to point of aim. I was overcome with the no (censored word). But then I learned how the FBI used to sight in their issued, 4” fixed sight S&W Model 10s. Put the frame into a padded vise and whack the end of the barrel with a leather covered lead billy.
I am almost 60 now and 45 years later the little Savage is the reason I love to carry a single shot in the woods and why I decided to try the Ultra Light 20ga. But this time I will overcome my now poor eye sight with a vintage Bushnell ScopeChief 1.5-4.5 scope. The same one I bought used and had mounted on my Dad's Browning 20ga B-80. Surprise, he took deer the next three years in a row, but wouldn't admit I had anything to do with it.
I’ll report back later this summer, sore shoulder or not.