Summary

Made a mould cavity of a generic speed feed for my rotor. A silicone mix is poured into the cavity, creating a cast of the speed feed.

Find a silicone mix with a shore hardness of 40 which is as strong as a pencil eraser.

Solidworks 2012 file uploaded for those wanting a different pattern. It is not fully defined fyi.

Instructions

Used Smooth On Mold Max 40 as my casting material which can be found here:

http://www.smooth-on.com/Silicone-Rubber-an/c2_1113_1135/index.html

Volume is about 9797.05 cubic millimeters (Solidworks)

For Mold Max 40, I had a two part mixture weighing around 15 grams which should be enough to fill the cavity.
Release agent isn't necessary, it will peel right off the ABS plastic
Use a utility knife to cut off any excess material.

NOTES
I thought about using Mold Max 60 (Shore Hardness 60) but was told that it tears easily. The Mold Max 40 is really hard to tear and is strong enough to stop the paintballs from pouring out.

You will need to de-gas the Mold Max with a vacuum chamber if you do not want any bubbles in the cast. I didn't have any vacuum chambers lying around and I ended up having a huge bubble trapped in my cast

Paintball Speed Feed for the Rotor - Mould cavity