How dangerous is it to shoot with oil in a barrel, the other day I forgot there was some oil in my 30-06 and put a round throught it, it hit the targed spot on and stil seems to be ok.

Most benchresters break in a new barrel shooting off a freshly oiled barrel. No problem except POI ususally changes. Note: the chamber is swabbed to remove oil there.
Oil in the chamber is not a good idea as it minimizes the cases ability to expand and grip onto the chamber walls and thus, the force of all that gas pressure is amplified back in the area of the case head. This can lead to excessively flattened primers and ejector marks. On a HOT Hot load oil in the chamber could easily lead to a blown primer.-Rob

Flip--

Too much of any liquid it a barrel will ruin it with one shot. The higher the viscosity the less material it takes. It's called hydraulic failure.

If your rifle is still shooting well, you're lucky.

Hydraulic failure is very easy to detect by slugging the bore. It'll have "ripples" in it.

I am very glad, looks like this could have been an expensive mistake.

If you look along the bore inside and out and can see no raised rings and if the jag goes through without suddenly easing at some point then you're OK.

Ringbolts are caused when the amount of oil in front of the bullet reaches the stage that it can no longer be pushed fast enough and the bullet rides over it. The fluid has to go somewhere and it makes a ring in the steel.

I've seen one rifle with 2 of these about 6 inches and 9inches from the chamber.

I had another look and it seem ok.