US Patent 9857131 Ammunition indicator systems, devices, and methods

An ammunition indicator system of the present disclosure uses a magazine configured for housing bullet cartridges, the magazine comprising an outward-facing surface and a cavity. The system further has a follower that fits within the cavity and interfaces with the bullet cartridges inside the cavity. The follower further moves in a direction toward an open end of the magazine as bullet cartridges from the cavity are spent. The system further has a channel in the outward-facing surface of the magazine and an ammunition indicator rod configured for slidably coupling to the channel and fixedly coupling to the follower, the ammunition indicator rod indicates an amount of ammunition in the magazine.