upgrade, cause you will not get the accuracy from the 870 with a rifled/cantilever barrel. The Savage 220f is one hell of a great shotgun that handles like a rifle.

Now by no means is the 870 no good, it has a great track record, and it would be cheaper for you to purchase the barrel, and you will have very good accuracy. If money is an issue get the barrel for the 870, but if you want a tack driver get the Savage 220f, or the H&R Ultra. Which ever way you go get a good glass and try various ammo to see what that barrel likes. When it comes to the 20ga I do like the 3" shell over the 2-3/4"