I think the reply Mark II gave about how long it takes to get out most of the oil is about as realistic as you can get. Nobody knows how long it has had to soak into the wood, and the idea that you will remove all of it in a weekend is probably a dream.
There are a lot of variables too, such as how much heat you apply. I have related the lesson I learned about using a large microwave oven to warm the wood on an Ithaca Flues stock. I kept wrapping it in toilet tissue and heating it for short periods in the microwave. I was amazed at how much oil kept coming out, and how quickly it was working. When I thought I was getting close to being done, I went a little longer on a heating cycle, and heard a fairly loud crack from inside the oven. I had gotten the forend too hot, and it split lengthwise. Fortunately, it was a very clean split, and a short acetone soak cleaned it sufficiently to glue it back together with Titebond II for a near invisible repair.
I've always felt that rushing to the finish line is nearly as bad as having little skills or talent when it comes to getting poor results when repairing or refinishing a gun. It helps to have other projects to move on to when there is ever the temptation to rush.
