You actually want the barrel real clean before you shoot. I swab the bore of my rifle with alcohol before I shoot. This takes the oil of of the bore. Then I load. After I shoot, I will take a patch, apply a solution, and swab the fouling out of the bore. Then a dry patch or two, and load again.

Swabbing solutions included a lot of things. A very common fluid to swab with is your own spit. Then there is Windex. There is solutions like Butch's Bore Shine, Rusty Duck, Simple Green, just about anything.

Some powders you do not have to swab. Others you have to swab with a certain cleaner. All of this you will learn. Is there any kind of rifle you are interested in?