My Custom M4. This was once a CA M15A4 C.Q.B.
Upgrade list internal:
M130 Spring
Prometheus 6.03 tight bore Barrel 363mm
Systema Bore-Up Cylinder Set for M4A1
Deep Fire High Performance Piston with titanium teeth
Systema Area 1000 Tappet Plate
Prometheus hop up bucking
Upgrade list external:
Standard length M4 outer barrel
Hurricane Colt M4A1 body
Midwest Industries RIS (Real Steel)
Hurricane Steel Body Kit