Question for you all. Have a TC Hawken that i had built as a kit approximately 20 years ago. Always had been a very accurate rifle. Progressively, the rifle would shoot high. Rear sight adjusted all the way down. Still approximately 1 foot high at 50 yards. Have always been very meticulous about cleaning after each day's shooting. After cleaning, would run a patch down barrel with WD-40 to displace any water. Have i taken the "seasoning" out of the barrel? Any ideas? Have not changed powder charges (90 gr FFg or RS Pyrodex) and .490 round ball.