During the firing cycle the bolt handle makes violent reversals of direction for each round fired. The
cantilevered portion extending outside the receiver (the finger piece) is subjected to
inertial forces and actually flexes back and forth on each shot. After a period of time, fatigue sets
in and the finger piece breaks off. Not only can you not cock the 76 / 760, the bolt has lost the guide
which keeps it properly positioned in the receiver.