Abstract: A pin puller for use in an automatic activation system for initiating the deployment of a parachute includes a small pyrotechnic actuator comprised essentially of a piston and cylinder. The cylinder includes a bracket through which the ripcord pin extends and which passes through the parachute pack closing loop. A thrust plate is carried by the forward end of the piston and is adapted to engage the loop. When the actuator is fired, the piston is prevented from moving forward by its engagement with the loop whereby the cylinder moves rearwardly withdrawing the pin from the loop. The entire pin puller assembly is carried on the exterior of the pack and is supported essentially by the interaction of the pin with the loop.