I have a Knight Disc Elite stainless steel, 50cal. inline. I noticed this problem last year and now that the season is fast approaching I am reminded of it again. Depending on how clean or well lubed the bore is, the gun may shoot high or low. I am shooting Hornady 240gr XTP sabots over 100gr 777 pellets. It is bad enough that I can tell by how hard the bullet goes down the barrel whether it will shoot high or low. If it goes real easy, 3" or more low at 100yds. Real hard, 3" or more high. My solution was to clean the barrel as best I could between each shot while sighting in. This helps, but it is a very fine line between easy to load and harder. The best I can do is get the bore as clean and dry as I can and hope for the best. Anyone else notice this?