Tommy 20 Nerf ring refit

Streamlines, elites and other such darts fall out of the tommy 20 due to the larger buzz bee dart thickness.

This design reduces the size of the holes slightly to grip onto the darts.

This will need to be glued in, as there is not enough friction to hold it in place.

The tolerances may need to be tweaked due to the fiddly dimensions, but should hopefully provide a design basis to go off of. (Printed on a geeetech i3 pro b at 230C, 3D fillies blue filament)