Barrel polishing process tips

Hi everyone,

I’ve just bought a 3l barrel machine and was wondering if I’m doing
something wrong along the polishing process. After I’ve sanded the
brass pieces from 180 to 600 grid, placed them onto my barrel with
stainless steel shot and a pinch of barrelit for about 2 hours my
pieces came with micro dots and looked like have been painted with
spray instead of a matte or satin finish, Have I done something
wrong? Any suggestions?

Thanks for any help,
Melissa