i have NEVER had ANY problems firing a round after the barrel was stored with oil in it.
I agree.
The term "lightly oiled" is the key here.
You don't need or want a dripping wet coat of oil in the barrel in the first place.
It is just going to run out during storage anyway.
Use a clean oiled patch, run it through the bore a few times, and call it good.
That will not leave enough oil to matter the next time you shoot it, and will not increase pressure or harm the gun if you shoot it out.
It will protect the bore from rust however.
And that's the way the military trains to do it.
As several folks noted, the first few shots from a rifle will not go where they are supposed to in a group.
If it's a hunting rifle, shoot it to foul the bore and leave it that way.
If it's a handgun you carry CCW, leave it oiled. It will not effect accuracy at all at SD ranges.
IMHO: Spraying aerosol spray oil down the bore should not be done.
Unless you wait for all the solvent to evaporate and then run an oiled patch down the bore to distribute the oil evenly.
The intense cold from an aerosol spray can cause condensation & mosture to form in the bore and cause more trouble then it prevents.
rcmodel