[Pendulum^-1]

Get a five gallon bucket from Lowe's/Home Depot. (I recommend getting several...so you don't hesitate to experiment/screw up...they cost us less than $3 each.) The buckets are great because they taper only slightly, almost imperceptably from the top to the bottom. Put a disc into the top....and it stops about 6 inches from the top. Draw a circle around the bucket where the disc stopped. Slice the bucket at this line or just above it, to establish the bottom edge of the hopper. (We used a Dremel with a metal disc cutter or sharp box cutter to cut the bucket.)

The slight taper in the bucket is nearly the perfect shape to keep the discs stacked, yet not nested so much that they do not separate or jam, and not so tight that they jam in the cylinder as they drop.

From there, experiment with an exit slot in the bottom (needs to be 1.4 inches high), a means to transition from the hopper to the chamber/shooter barrel (we use a pneumatic piston, without any clevis attached), and a means to feed it. For feeding, we cut about 225 degrees around the uphill and top edge of the bucket, cutting down about 1" from the top. With the sloped cover to the shooter, we have a good backstop for discs to hit, and drop into the hopper.

Dozens of examples are shown in the reveal videos. Your own geometry will vary, depending on you shooter configuration and space available on the robot.