You can get full-moon clips that work with the M1917 from Ranch Products. (Midway also sells them). Half-moon clips are also available, but they tend to be rather flimsy and get bent easily. They were designed to be used once and discarded. My favorite is the third-moon clip. They are easy to load/unload without tools and ammunition so clipped stores easily in an ordinary commercial ammo box. All these are available from Ranch Products or Midway.
Here are the three types mentioned above:
