I had a Poly Choke put on my Mossberg 500 16 gauge. With the higher bead put on by Poly Choke the gun shot about 10" low at most ranges. I researched barrel bending and found some techniques used by trap shooters. Sure enough I was able to impart a slight bend (not visible to the eye) and corrected the point of impact. The idea I used was to remove the barrel (holding the chamber end) and then strike it against a full bag of lead shot hung over a deck railing or tail gate. To bend yours upwards you would hold the chamber end and strike the bottom of the barrel. I did mine at my shooting area and corrected it in no time. Just a suggestion. Mine printed slugs and shotloads low until I fixed it. Do a I net search for shotgun barrel bending lots of techniques and it is not as scary as it sounds.
Darryl