Your guess is as good as any. Some rifles, not any of mine, do shoot better after a slight fouling. I believe that this is because of bore size issues. A friend of mine shoots 10 grains of powder before he loads to go hunting. Even when were at the range he does it. I pour my own maxi hunters and we both shoot bullets from the same box on the bench. He can't hit center on his first shot to save his life if he doesn't foul his barrel yet none of mine have any trouble, even if he is shooting the gun. Maybe his bore is just a tad bit larger than the normal, or he needs a Thompson Center. LOL If any of you shooters come up with an answer I'll pass it along.