The shoot x/clean, shoot x clean repeat repeat thing might be debatable, but what isnt debatable is the fact that the barrel must be clean and free of any material including the layer of lube left in there after cleaning or in transport. To reiterate, oil in the barrel, of sufficient quantity,
will damage the barrel. .... Its obviously important to leave a protective layer of lube inside the barrel and chamber after cleaning, but even more important to remove it before shooting, from the barrel AND the chamber.
Oil in the chamber will -remove- the necessary friction between the case side walls and the chamber upon firing, thereby INCREASING the thrust on the bolt face = bad.
Oil in the barrel may/will bulge the barrel....if you can imagine a layer of oil inside the barrel; as a bullet moves down the barrel from the chamber it will move(sweep up) the oil as it travels and will get to a point, very quickly, where the oil between the front of the bullet and the barrel NEEDS to go somewhere, it can not compress (hydraulic fluid are very useful due to that property), can no longer push it forward, so either the bullet
collapses or the barrel expands.....to allow the bullet to 'move past' the oil. When the oil wins - the barrel loses, and expands. Enter the barrel 'bulge'.
So clean your barrels after shooting, but never forget to patch out before.