An attachable storage receptacle for storing an accessory on a firearm comprises a storage receptacle body having a top portion, a bottom portion and a wall portion, and an attaching mechanism on the top portion of the storage receptacle body for releasably attaching the storage receptacle body to a bottom end of a firearm magazine. The wall portion is connected to the top portion at one end and the bottom portion at the other end, thereby forming a hollow inner portion for storing the accessory in the storage receptacle.