Features:
Based on WE Tech GBB Airsfot Rifle
Modified with Z-Part MK12 MOD1 CNC Steel Set
The Silencer is Optional Choice
CNC Steel kit from the Z-Part 
Nice Recoil and the shooting feeling
Almost full bolt travel
Hop up adjustable in the breach
Base on the WE system M16A3 GBB Airsoft
 
More Optional:
Add Silencer
Add 20rd short Magazine
Upgarded Inner barrel and Hop-Up Rubber
 
Infornmation:
Model: MK12 MOD1
Materials: Steel, Zine Alloy, Alloy, Nylon, Rubber
Length: 950mm
Weight: 4000g (8.11 pounds)
Barrel: 510mm inner barrel
Power Source: Green Gas
Action: Semi / Auto
Ammo Type: 6mm airsoft BBs
Ammo Capacity: 30-round full-size metal magazine
FPS: 400
Bunker Tech Upgrades
Maple leaf gbb 6.02mm Inner Barrel
Maple leaf  High Accuracy Hop-up Bucking- Internal Parts Adjust
All function checks, to avoid common tolerance issues.
BB weight for optimal performance: 0.36 gram