I suspect the switch drop tube is the same as the proximity version on the bottom. I use the APP tube adapter (APP_Drop_Tube_X_Adapter) 3/4 fits the large clear tubes that come with the Lee feeders. The other side fits the bottom of the drop tubes. I imagine the small tubes will fit one of the other sizes, but I haven't tried it. So I just cut about 2" off the end of one and used it as an adapter between the drop tube and the APP case feeder tubes. I'm using it on the case side, but looking at the bullet feeder parts, I think it would work the same way.