.177 CAL BB.
thingiverse
It's a .177 caliber BB that measures 4.5 millimeters in diameter.
Download Model from thingiverse
With this file you will be able to print .177 CAL BB. with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on .177 CAL BB..