CO2 12g air cartridge holder stackable

This is CO2 12g (19mm diam) cartridges stackable holder.
It parametric model in Fusion360, so I can generate this for any cartridge size and diameter.
This version was modeled for 19mm diameter 12g cartridge and has 50mm height.

Updates:

• upd.05.09.2019:
  some improvements for better stacking. still not printed.
• upd.08.09.2019
  v8 was printed and seems to be good stacking)