So this is what the inside of the Ma40 ammo counter looks like. It has a Faux Ammo counter that goes inside of a "window" plenty of mod capabilities. : r/Nerf
REVIEW] NERF Ammo Counter MK4 (THE BEST NERF AMMO COUNTER YET!) - YouTube
Nerf gun upgrades! Mod your nerf gun with a Raspberry Pi
Nerf Dart Ammo Counter Review | Nerf Gun Attachments