RE: 12 gauge to 20 gauge....your opinion
You might want to take a good look at why you're not hitting with the 12. What kind of sights are you using? Under what conditions are you missing? Is there a difference in your hits at the range v. in the field? Also, have you tried different barrels? I bought a brand new rifled barrel for one of our Remingtons a couple of years ago and couldn't hit crap with it. That was a 20. I was out of the bull at 75 yards, a range I routinely nail with a 12.