Polishing will make the bore much easier to keep clean. Get you a bore snake and during the season, use it dry several times thru the bore every time you shoot it and also any time the bore might have gotten damp. Once per year scrub the barrel with brass brush and good powder solvent. Swab the bore with solvent first and let it sit a while, then scrub it with more solvent. Then patch till clean and dry. If there is moisture where you store the gun then give the bore a light gun oil but remember to clean the oil out before next season. There are lots of good solvents out there, pick one that says it will remove powder, plastic and lead.
