Rounds are loaded from the front of the gun  and pushed to the far back with an aluminum rod.

子弹从枪的前部装填，然后用一根铝棒推到枪的后部。

Initially they tried using only rubber bands connected to hinged aluminum rods, but with this design when compressing it, the force rises to a peak and then decreases.

最初， 他们尝试仅使用连接到铰接铝杆的橡皮筋，但通过这种设计， 在压缩橡皮筋时，力会上升到峰值然后减小。