Souds like you have scrubbed and cleaned the bore, but are still removing residue/rust. Try good old fahioned Hoppe's # 9. Swab the bore with a saturated patch, then a dry one. Do this several times. Next, Run a saturated patch down the bore, and let it set overnight. This will dissolve lead, copper, crud, etc. Next day run a dry patch thru. You may have to do this for several nights, but it works. Forget about the "seasoning". This is nothing but a marketing ploy to sell Bore Butter, which IMHO is the worst thing you can use to prevent rust, and corrosion.