Ống phóng lựu Airsoft 40MM Tự Chế

8x M3x16 screws
4X M3x30

2x m3 Square Nuts (can be replaced with hex nuts)
8x M3 Hex Nuts

3X 6X20 springs

The springs are used for the trigger plunger and the picatinny lock
an M3X16 screw goes into the head of the trigger plunger to give it extra strength

Update:
I modified the Lug Cap/Rail and picatinny lock pieces to be stronger and less likely to break around the lock area. 

Edit:
Added some strength to the Lug Cap and Rail. but now requires small supports
Added STEP files