Hardware

Two small pins, I used a sewing needle cut down.

Two small springs, about 4mm diameter. (One for the mag catch and one for the BB stopper)

One BB 

Printing

Print on the edge as shown in the photos. 

No support needed

Assembly

Put one of the springs onto the catch and then push it into place, from there push the pin through and that bit should be done.

For the BB stopper put a BB in the hole that goes into the BB feeding tube, then a spring and then push the BB Plug part in and pin that in.

From there you should be good to go.

Notes

I have not done too much testing but from what I have done it seems to work fairly well.

I have found the mag doesn't like fitting in if the little lever on the back is down, fitting in with it up is tight but it pushes just enough to bring the follower down if the mag is empty to allow it to be filled.

If anything breaks let me know and I will try and make it stronger.

If you do fully fill up your mags I would recommend taking a couple of BBs out so that there is less wear on the nozzle.

Also to note is that the BB retention system does add some extra strain on the Odin and I have found it works fine without it. You can print the standard version and just not use it and that works or I have uploaded another no BB retention version that you could print.