I shot my Omega last weekend from a completely dry bore and the first shot was 1 inch higher at 100 yards than the next two. But, the next two cut through the same hole making the group just over 1 inch. I swabbed the bore with two alcohol patches and two dry patches and started shooting. I may try fouling with a couple primers next time and see if there is any difference but I would not hesitate to shoot from a perfectly clean gun. Oh Yea, this was with BH209. My first time shooting this powder and all the reports are dead on. This stuff is amazing and made shooting a lot of fun. I may not take another rifle to the woods this year.