A lot of this will depend on your personal rifle's characteristics. The first shot might be right on, and all the following also. You will not know until you try the rifle and the projectile. Also there are a lot of shooters that believe in fowling shots. My grandfather used to claim his deer rifle shot better with a dirty barrelthen clean. We always figured he did not like cleaning his rifle was all.

Some rifles have a big difference between the shots on a clean barrel and a fowled barrel. You will have to shoot it to tell.