I'm no gunsmith,but sounds to me you have some burrs or ill fitted parts and it only comes into play when the action is fully loaded and cocked...seen this before on a couple of Classics and one rifle seemed to pick when it wanted to chamber a round.One rifle would not close into battery.
The problem might be at the nose of the bolt or could be on the back end.Mine was on the backend...my smith fixed it.You should take it to your gunsmith.
