Some people find that a rifle shoots different from the first shot on a clean barrel to the consecutive shots on a dirty barrel. The purpose of fowling the barrel is to make all the shots the same. So they dump 20 grains of black powder down the barrel, then push a patch or two on top of the powder and touch it off. They then swab the barrel like they had just fired a shot and load as always.

Others who do not want to fowl keep very close account of where the rifle shoots on a clean bore and a dirty bore. Say for instance on a dirty bore the rifle shoots two inches low and an inch to the left. So they load the rifle clean, have the scope or sight set to the clean barrel and make their first shot count. Should they need a second shot they know they have to aim two inches high and an inch to the right.

Not all rifles chance the POI between a fowled and clean barrel. You need to shoot the rifle and the projectile you want to hunt with a couple times, taking note if there is a difference.

If you fowl the barrel you have to clean the rifle that night after the day of hunting. Another disadvantage to the fowling of the barrel....