In the chute there is a grid that is the particle emitter. When I hit play, most of the particles properly bounce into the box, but quite a few keep going straight down (I have a 'force' set to -3 on the Y-axis for gravity). Also, once the particles stream into the box, they hit the far side, but only half of them actually it the bottom of the box. And even these bounce right through the wall they just streamed down. I'm currently using slide collision, but have tried bounce too.
I'll post my scene in a bit. I've got to burn it onto a CD from my workstation.