Theses spare shells it the “Nerf” shotgun currently sold at B&M in the uk, with wich you get 6 shells that eject with force and are easily lost  when playing with the blaster.

Might fit the Tolov Zerky blaster out of amazon, but i havent tried it.

These increase fps slightly and can be used with both short, ¾, and full size darts.

Print with atleast 3 walls and 15% infill, increase for durability. Pla works fine, but you should printe in bright colors so theyre easier to find once ejected.