I've had Hasselblads for many years and they do sometimes jam. invest in an unjamming tool. It has two protected ends. One for the camera body and one for the lens. Don't go out without one and a dark-slide. You can't fight Murphy's Law.
Good idea - I use the tool as well, though it is a bit heavy, so it stays in the car along with a small jeweler's screwdriver.
Make sure to print out the unjamming instructions to keep along with the tool.