My needs may be different still......I wanted the APP to deprime and swage military rifle brass, both .223 and .308......and I ran into to some problems that needed to be improved upon......feeding long cases isn't as trouble free as feeding short pistol brass. The long cases don't fall straight....especially the lighter .233. So I made 1 7/8" drop tubes out of rigid thin wall that press fits into the bottom outlet holes of my 4 tube feeder. Below:
Attachment 259291
You have to raise the feeder 2", but the feeder screws are plenty long. Picture of each below....the .308 is 9/16 O.D. tubing, the .223 is 7/16" O.D. tubing with two turns of aluminum tape on the top 1/2" to make it press fit tight into the smaller outlet hole.
The object is to surround the cases tighter stabilizing the cases on top of the shuttle and controlling the fall better to the rail.
The .308 drop tube is demoed in the video below:
the smaller lighter .223 was still giving some stabilization problems and I discovered that the bevel the cases go over at the end of the shuttle just before they drop was the problem......the fix was to use a Dremel sanding drum and grind the bevel off.
Attachment 259289
Above, picture shows the bevel on each shuttle piggy back
Below, picture shows the bevel ground off on the tall piggy back
Attachment 259290
Below, the video of the .223 going through much better using the drop tube and the de-beveled shuttle: