PJWRKS gives us a quick tour of his concept for a 3D Printed Airsoft AAP-01 Halo M6 Magnum Kit... "Airsoft aap-01 HALO M6 magnum dress up kit V2 for airsoft use only.  The flashlight under rail is not included. This uses PLA+, infill over 50%:

• 2 M3.5x5mm screws are used to fix the RMR
• 2 m3x8 screws are used to fix the lower rail
• 1 M5x30mm screw is used to fix the slide
• 1 M3x8mm screw is used to fix the magwell
• 2 M3x8mm screws are used to fix the upper rail"