Bullet Casings for Revolver Fidget Spinner

This is a tweak to the bullet casings for the Revolver Fidget Spinner by iTzOminous Tic.
http://www.thingiverse.com/thing:1977070
I added a "lip" to the bullet casings so there is no need to glue them in. These should just pop into the holes without glue. I also hollowed out the inside of them to hold a standard size metal BB pellet (4.5mm) between each cover to add weight to the spinner. I am very new to 3D printing (this is only my 2nd day) so the lip looks pretty rough when printed but i