Airsoft 3D announced a new product designed to make the Angel Custom AP10 MP5 Mag Adapter to be used for the APS UAR AEG as it uses M4 mags too... "Evike's Angel Custom AP10 is a well known magazine converter that lets you use MP5 magazines on M4/M16 and other airsoft electronic guns (AEG) that have the standard STANAG mag well. That means the APS Urban Assault Rifle (UAR) should be able to use this MP5 conversion as well. Unfortunately, APS UAR's mag well is too shallow to keep the MP5 magazine in place when the Angel Custom AP10 adapter is in place.