Problem, locked up bolt on Rem 700, easy solution. The Rem bolt has backlash, meaning the bolt when closed on an empty chamber will go farther forward than when it has a properly loaded round in it. Now when a over loaded round fired in it the case doesn't spring back enough to relieve the contact with the bolt head. A couple things to mention, a new case will spring back better than a well used and not annealed case. Now to the easy fix, the bolt when locked up is at its rearmost position. The cocking piece is screwed into the rear of the bolt, actually looks like a bolt screwed into the bolt. You can tap or pound on the rear of the cocking piece to resize the case enough to open the bolt. I would use a piece of wood of something to cushion the cocking piece. This would have work on this rifle, looking at the case tells me it was not grossly overloaded.