When I do my practice shooting I first clean my barrel with 91 percent alchohol to get the oil out of it. (I think sometimes peoples first shot is different due to oil in the barrel but I am not sure of that). Then, between shots, I swab with an alchohol dampened patch, first one side of it then the other. Then a dry patch. I do not notice much if any difference between my first shot and my other shots. I also use conicals that are fairly tight in the bore. I suspect some of the people that have quite a bit of difference after their barrel is fouled are using a projectile that is a little bit loose in a clean barrel. Again, I am not sure of this because I am not around other shooters much at all, I just know what works for me.