Introduction: DIY Full Auto Airsoft Rifle

About: I like to create things, handmade weapon, arduino projects, science and some crazy staff! Also I like to capturing videos about my projects and I have YouTube channel - MadGyver!

GyverGun is Arduino based full-auto airsoft rifle made of very common components and materials. It is capable to shoot 2 steel 4.5 mm BB balls per second with muzzle energy of about 3 Joules. Compressed air is controlled by solenoid electromagnetic valve (truck horn), reloading mechanism is servo. GyverGun has safety switch and fire mode switch (semi-auto and full-auto).

  • 2 shots per second
  • Servo powered reload
  • Shoots BB 4.5mm airsoft balls
  • About 70 balls in magazine
  • Muzzle energy 3 Joules
  • 10 bar pressure tank
  • Semi-auto and full-auto fire mode

Scope is handmade too, just old binoculars with lens modification, you can watch a video about how to make it here

It's first version of handmade pneumatic full-auto rifle, there will be some update in this year (10 shots per minute bolt =)

Watch a video about GyverGun, there are more detailed instructions there.

Step 1: Air Tank

Air tank is made of montage foam cylinder with plastic cap (foam for foam gun). It is very important! Empty the cylinder and let all gas go away. Then get rid of all valve parts (just drill it). Take 1/2" fiting and make a thread in plastic cap. Use burner to heat fiting and "melt" the thread. Then use epoxy to fix fiting in cap. So you need a cylinder with 1/2" and 1/8" outputs.

Step 2: Valve

Take a tubeless nipple and glue it in 1/2" stub with driled hole. Use rubber glue.

Step 3: Solenoid Valve

This project is based on solenoid electromagnetic valve (truck horn part) from Aliexpress. It has 1/8" input and 1/4" output, can control compressed air at 15-17 bar. You can find all links on project components here, on project's GitHub page.

Step 4: Barrel

Balloon stick is very good barrel for 4.5mm BB ball, but very soft. So I made coaxial barrel with 8mm and 12mm aluminum tubes, using thermal shrinking tubes between aluminum tubes. Looks tricky, but shoots very good!

Step 5: Barrel Adapter

Use any 1/4" fiting, 8mm aluminum tube and cold weld to make 90 degrees adapter.

Step 6: Bolt

The most hard part is a bolt: it must be easy sliding, but very tightly. Also it will put BB ball into barrel. I made bolt from drop counter part and piece of balloon stick.

Step 7: Attach Barrel to Tank

Use cold weld to make it

Step 8: Reloading Mechanism

Attach servo to adapter and a tiny magnet unter the barrel

Step 9: Reloading Mechanism Part 2

Make a guiding rod (nail and pen core) and connecting rod between servo and bold (I used clip). Also make ball feed system (cold weld and PVC tube). Watch a video to see how it works.

Step 10: Ball Holding Magnet

Add a magnet to hold ball inside barrel

Step 11: Electronics and Code

Scheme is simple, all information and Arduino sketch in on GitHub repository

Step 12: Rifle Handle and Butt

Use wood and PVC tube =) More details in video

Step 13: Rifle Optics

Optics is modifyed binoculars part, there is video about in on my channel. Fix it in tube with screws for adjustment

Step 14: Final and Tests

So, GyverGun is ready to shoot!

MadGyver (aka AlexGyver) for Instructables.