Both small and large Dillon Primer pickup tubes:
Small Primer tube = .183 ID x 5/16" OD
Large Primer tube = .215 ID x 5/16" OD
Note: Does not include the end fittings.
These are in 6" lengths, so use the 30mm long connector to put two together and make a standard 12" primer tube.
You may need to play with X/Y scaling in your slicer to make the sleeve a perfect fit (design drawn at .1mm clearance).
The author hasn't provided the model origin yet.