3D model description
Airsoft carbon fiber upper receiver designed for standard m4/ar15 replicas featuring fiber sights, a red dot mount and an integrated tracer unit achieving durable, light weight and narrow profile speedsoft build for both - AEG and HPA systems.
SUITEBLE GEARBOX: V2 standard.
SUITABLE HOP-UP UNITS: All.
SUITABLE TRACER UNITS: Acetech Brighter C, Brighter R, Brighter CS and any other with outside diameter of 28mm.
SUITABLE LOWER RECEIVERS: Tested on Specna Arms Core series and similar replicas. For other receivers - space between the front pin holes has to be ~16mm, Length from the front pin hole center to the back where upper receiver slides in has to be ~182mm, Width of inner space in the back where upper receiver slides in has to be ~32mm. If Your measurements slightly differ, don`t worry. With slight adjustments the upper will slide right on.
REQUIRES:
- Three 3d printed parts (upper receiver, front sight, tracer thread insert).
- Carbon fiber tube (30mm OD, 28mm ID) which is available on Amazon, AliExpress etc. I have also added a 3d model of the carbon fiber tube in case You can not get one.
- Three ~7mm long m3 screws and three ~5mm long m3 threaded brass heat-press inserts.
- One 3mm fiber optic rod.
INSTALLATION:
Carbon fiber tube preparation
1) First choose the length of Your upper and cut the carbon fiber tube as short as You like (I prefer ~36cm).
2) From one end make a straight 19mm wide and 182mm long square cut out. And another straight 9mm wide and 152mm long square cut out right above the other one. (This smaller cut out on top allows to slide the upper over a V2 gearbox without modifying it).
3) Upper receiver and the carbon fiber tube connects with two m3 screws in the bottom of the front. Drill two 3mm holes in the bottom of the tube right in front of the 182mm long cut out. First hole 5.5mm from the cut out, second hole 18.5mm from the cut out.
4) Front sight and the tracer thread insert attaches to the tube with a m3 screw on the top. Slide the carbon fiber tube in the upper receiver, put on the front sight and align it with the rear sight. Take a sharpie and mark the front sight screw hole on to the tube and drill a 3mm hole there.
5) To make hop-up adjustment cut outs drill a ~14mm hole on each side exactly how You see in the pictures. Use sandpaper/file to perfect the holes if needed.
6) (Optional) - If You want to use "Front sight V2" a 25mm horizontal hole is needed in the front of the tube. Drill it through both sides and cut the tube right in the middle of the hole. Then adjust the tubes end with sandpaper/file until the front sight fits perfectly.
3D printed parts preparation
1) Use two ~5mm long m3 threaded brass heat-press inserts for the upper receiver. Heat press them in to the two holes on the bottom of the front using soldering iron. Use the same technique for the tracer thread insert hole.
2) Complete the build by sliding the tube in the upper receiver and screwing two ~7mm long m3 screws in the front holes. Slide the tracer thread insert in the front of the upper, put the front sight on and attach them both to the tube with a ~7mm long m3 screw.
3) Put a 3mm fiber optic rod in your front sight. Cut off the ends and torch them for a few seconds using a lighter. Screw in Your tracer unit and You are all set!
Feel free to contact me about any questions for installation process and the build:)
Cheers!
3D printing settings
The printing position is already set correctly, but tinkering around to find the best printing position for Your exact settings would be great.
FDM printing: abs/petg/pla will do great. Use supports and maximize infill for greater strength.
SLA printing: abs-like resin recommended to reach higher strength.