I never put gun oil in the barrel unless its to be stored for any length of time, wich not many of my firearms are. If you swab even lightly with oil after cleaning and go hunting the first shot (which usualy will be your highest percentage shot will be off its mark ) will be different than when it was slightly fouled. I always sight in and then run a few dry patches and maybe a dry nylon brush through if I fired more than four or five shots sighting in. I have found that a lot of rifles fire a tighter group when slightly fouled. Just my experience.