If it's dinging the sides of the chamber feed ramp (little nicks on both sides), the barrel is hitting the "locking insert" not the take down lever. Those nicks are standard fair on Sig 220's when the barrel is not pushed all the way up into the slide before assemby or the spring/rod left out and assembled.
Here is a pic of my barrel, yes it has nicks as I am not very careful with assembly. They are highlighted in red. The yellow is the normal wear from actually riding over the locking insert. The Red is nicks from ramming "into" the locking insert instead of riding over.
Two ways I see this (red nicks) usually occuring. THe first way is people like me who will install the barrel without spring or guide rode and mess with the action. The spring/rod, normally pushes and keeps the barrel fully up into the slide on assembly so it clears the locking insert, but without spring/rod, the barrel will fall downwards and ram "into" the locking insert.
The other way it usually occurs, is that on assembly, either the barrel is not fully seated into the slide or the palm of the hand holding the slide pushes the barrel downwards alittle and it rams into the locking insert.
Note that this feed ramp damage does NOT affect operation or function, just looks odd. Bullets never touch the edge areas during feeding.
Assuming, the 2 things are not happening to you:
Now the verticle space/distance of the barrel heighth (top of chamber to bottom feed ramp) on a Sig is very close in tolerance. What "could" have happened is that the additional thickness of nickle on the inside of the slide (just in front of ejection port) is pushing the barrel down just enough
so that edge of feed ramp is banging into the locking insert (yellow area of picture). If you have damage higher than this edge, one of the other two listed issues is happening as nickle does not add that much thickness.
You can fix the issue with a file if it is indeed hanging on the locking insert. Easiest way for a novice who doesn't handle files a lot, is to buy some auto painting 600+ grit at the auto store (black color), put on edge of flat table and just press bottom of barrel ramp on it and sand off "TINY" bit at a time until the barrel/slide goes onto the frame. Or you can use files, but files take off material MUCH faster than 600 grit sandpaper and is not as forgiving of mistakes in judgement.
Before you go sanding/filing away though, I suggest you make sure that A; there is nothing on top of the barrel (right by top shoulder area) and nothing under the slide (front of ejection port) that is keeping barrel from COMPLETELY seating into the slide. B, the barrel is indeed seated all the way into the slide by spring/guide rod and nothing is accidentally pressing it down as you assemble.
Or you can just send everything to Sig like you should have the first time. It is not Sigs fault if they can't test for proper operation, and being a LEO is no excuse. The barrel/slide/locking insert fit is the highest tolerance part for Sig accuracy and proper function. Hundredth of an inch matter here (as you are finding out). Sig isn't the only one who will tell you tough luck for such an essential part functionality after a refinish that changes the dimensions of the slide without having the parts for test fitting.