UPDATE
I created an integrated feedneck to replace that glued in one. If you want to use the feedneck, print the bolt cover with FN in the name. You'll need some hardware and to drill and tap your body.

For the bolt cover to feedneck attachment I used M4 bolt and nut.
For the feedneck to body screw i drilled and tapped 8-32, which is the same size screw as a Phantom. You don't NEED to do the drill and tap, but you are doubling the strength.

I remixed this design originally to remove the detent hole and switch it up to a #6 set screw. I found that it was a little tight on the bolt as well. Changes below:

1. Uses #6 set screw for retention
2. Shortened slightly to fit my Rainmaker
3. Set back the bolt cavity slightly for more clearance.

EDIT I Changed the size of the file. You should not have to print at 102 now, but I still needed to use a heat gun for the first time I fit the cover to the body. It will be TIGHT until you heat and fit it.