Abstract: This invention is a motion control mechanism for use in electric toy guns. The mechanism includes a gear set, a piston set that is inside the electric toy gun's body and driven by the said gear set, a primary repositioning spring that is between the said piston set and the toy gun's rear end, and the repositioning set that is installed on the gun body, and moves backward when driven by the said piston set. The said repositioning set is fixed to the piston set, and will move backward when driven by the gear set. It will then reposition itself by the force of primary repositioning spring. The electric toy guns with this invention have the following advantageous features: Since it has a repositioning set, and air release holes, it provides for motions that are more similar to those of real guns. Thus it is more suited for military training and lasts longer.