From G&G we have a Drum Magazine for M4/M16.
The Magazine
This is a replica 5.56mm Single Drum Magazine for AEGs. It has a 2300 round capacity and is constructed from polymer. It is loaded via a window at the side of the magazine and features an inbuilt electric motor with an activation switch on the back of the drum for tensioning the magazine. This magazine uses standard 7.4v AEG Batteries that are housed internally to operate with the compartment accessed by undoing the bolts around the edge of the drum and carefully splitting it.
Compatibility
This magazine is designed for G&G’s M4/M16 Series of Replicas but it is also widely compatible with many different brands of M4/M16.