Don't worry about the take down screw. It is a captive screw. Once unscrewed it will pull through the action and stop prior to coming all the way out. You did pull it out through the action, right?
When the two pieces of the rifle are pulled apart, the bolt and bolt handle come out with the front half which in your case is what the bolt is hitting. The rear half houses the firing system. When you are trying to separate the two halves, hold the pistol-grip with one hand and pull the front of the rifle straight forward. They come apart very much like a semi-auto pistol.
Don't get mad at me for asking basic questions, please. I am just trying to get the easy things out of the way. Have you removed the magazine from the rifle. I just tried taking my 611 apart with the magazine in and I had the same symptoms you are describing. Also with the bolt back and the magazine in, the bolt will not go forward. You have to remove the magazine, then pull the bolt handle rearward slightly and then release it to go forward.
If you have done all of these things, get back to me, and I will investigate further using my rifle as a test bed.
Good luck.
