Originally Posted by duhon19
Wouldn’t the reloading mechanism begin to move the instant after the projectile passes D1? What causes the delay?
The delay comes from the gas system it self. The system rests at atmospheric pressure. Upon the passing of the bullet and the pressure spike in the gas system there is pressure and volume that must be gained in the gas system. The volume of the gas system may be very small but when your talking milli seconds, its enough to delay the action. Other factors involved are the force coming from the recoil springs. They play an important role in action timing. To heavy, the action will not fully cycle and be late in its cycle, if it even cycles at all. Too light and the action open too soon, loosing barrel pressures, risking separating a case head or bulging a case and/or just flat out bashing the action to death.