The oil I use is outers, and I usually swab it through on a well saturated bore mop, then push a tight oily patch through to get out the excess. The crazy thing is, I got my rifle out about a month ago just to wipe it down and oil the bore, and It was slick as glass. The weather here in Arkansas has been anything but humid, driest summer I've seen in a while. I hunt in the rain, and muck all season, and have never had this happen. The only possibility I can even remotely consider, and it may be a stretch, is that during the winter I was polishing and bluing a hatchet head, I had my oil next to the sink where I was cleaning and degreasing the metal, some water may have gotten in the open bottle, and subsequently been applied to my barrel. Like I said a stretch, but maybe???