An acceleration-sensing loader activation system can include an acceleration sensor configured to generate an electrical signal corresponding to the magnitude and periodicity of movement of a marker or loader body or a marker or loader component. A signal filter circuit can be arranged in communication with the acceleration sensor to receive and filter the electrical signal. A signal amplifier circuit can be arranged in communication with the signal filter circuit to amplify a signal from the signal filter circuit and transmit the amplified signal to a signal processing circuit. The signal processing circuit can be programmed to evaluate the incoming signal and determine whether it corresponds to a desired actuation event (such as a firing event). If the signal processing circuit determines that a desired actuation event has occurred, it can then send a control signal to a control circuit to activate a feed device of the loader. A method of activating a loader assembly preferably includes using an acceleration sensor to detect movement of a paintball marker or loader's operating mechanisms and/or body and to output an electrical signal proportional to the magnitude and periodicity of the movement. The resulting signal is then preferably processed using filtering, amplification, and digital signal processing circuitry to determine whether the movement corresponds to a desired actuation event and, if so, to provide an activation signal to activate a loading operation of the paintball loader's internal feed mechanism.