RE: Oil in the barrel /will it cause misfires?
Yea, you should get it out before firing. I use No13 to get it out of inlines. You don't want borebutter really in a an inline in my opinion. So I shoot off 2 primers or caps. Then wipe it out with No13 from T/C.
Its best really to go hunting with a fouled barrel in my opinion. One that has been fired once and cleaned out.