A slower longer push (slow powder burn) seems to be more forgiving than a fast kick in the but (fast powder burn) especially as peak pressures pass about 50% of max and go up from there even of peak pressures of both powder types are roughly equal. This too then would lend credence to the torque issue I was speaking of. Give the wrench a quick hard smack and the lead bolt might break. Apply pressure slowly and maybe it turns.