Originally Posted by molybdenum
That still wouldn't work if I wanted to get the ball behind the detent, because the tube would interfere with the draw.
It shouldn't interfere with the draw because your barrel + detents don't have to end right at the hand grip of your bow. You should be able to extend it another 6-8 inches without any flex in the pipe. The stick feed being on the right hand side would allow you to draw back with your right hand unobstructed.
The detents aren't being used to keep the paintball at one spot inside the piping, but only to not allow it to roll out the front of the piping.
As shown in my render, your design of the slices down the center of the piping wouldn't need to be changed at all. The only thing that may be necessary would to slice a notch in the top and bottom on one of the sides of the T piece so the drawstring could go all the way forward. Even with the slices in the T piece, there would still be enough strength for the material to hold onto the piping pretty easily. And if not, you could always use epoxy to completely make the T piece stationary.