There are two main ways to build a homemade Airsoft gun: one method uses your breath as power, while the other uses an air compressor. Both techniques are quick and result in a functional and powerful tool. Choose your preferred approach and begin with Step 1 below.
Instructions
Fast and Simple
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Drill two holes in a small container. Any small container with a lid will work — a pill bottle, a film canister, a plastic soda bottle, or anything you have on hand. Just be sure to clean it first since you'll be putting the opening in your mouth.
- One hole should be drilled in the center of the bottom, and the other in the side of the container.
- For a standard pen, a 5/16" drill bit is ideal, but the size may vary. Select a drill bit that corresponds with the width of your pen since it will be inserted through the hole soon.

Disassemble a basic pen. You know the kind they hand out at hotels or conferences — a simple, ballpoint pen with a straight tube and no extra features. Follow these three steps:
- Remove the cap covering the ink tip.
- Take out the inner components — the ink and the spring — leaving a hollow barrel for the BBs to travel through.
- Use a screwdriver or any pointed tool to push out the top cap.
- A strong straw can also work for this step.

Place the pen into the hole at the bottom of your container. It should extend about 1/2" (1.25 cm) into the inside of the container. A standard pen should fit securely into a hole made with a 5/16" drill bit.
- It's recommended to use hot glue to attach the pen barrel to the bottom of the container. Apply a glue ring around the pen where it touches the container's edge to prevent air from escaping, ensuring pressurization for the BBs.

Unscrew the cap and add BBs. Fill it up just below halfway for optimal performance.

Blow into the side hole and watch the BBs shoot out the barrel. Experiment with distance and accuracy — you should be able to launch the BBs a fair distance (like the length of your garage) while maintaining control and speed.
- Make sure not to inhale while your mouth is close to the container. Inhaling pellets could cause choking. Instead, take a breath away from the gun and then blow through the opening.
Using an Air Compressor
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Attach the adapter to the blowgun and remove the nozzle. We're referring to a blowgun that connects to an air compressor — not the type you'd use to launch poison darts at an unsuspecting target. Secure the adapter by screwing it in until it's firmly in place.
- The nozzle (the part that would normally connect to the air compressor hose) can be unscrewed by turning it counterclockwise.

Drill a hole in the side of the soda bottle. The hole should be about 1" (2.5 cm) beneath the bottle's top bulge. The size of the hole should match the nozzle of the blowgun that you removed earlier.
- If you followed the previous method, a standard pen requires a 5/16" drill bit. The nozzle will likely be a little larger than that.

Insert the nozzle into the hole from the inside. This part can be tricky:
- Place the nozzle inside the bottle.
- Using a metal file or any other long, slender object, guide the nozzle into position.
- Fit it securely into the drilled hole with the threaded section sticking out.

Screw the blowgun onto the nozzle. While doing this, hold the nozzle steady with the metal file to prevent the weight of the blowgun from dislodging it. Take your time as you screw the blowgun onto the nozzle.
- Once it's tightly secured, the blowgun should be stable and immovable. At this point, the soda bottle and the blowgun base will be firmly attached.

Drill a hole in the bottle cap. The hole should match the size of your brake line. It's best to start with a slightly smaller hole and gradually enlarge it if needed — though you could always just find another bottle cap if necessary.

Attach the brake line to the bottle cap. Pull the line through until the entire tube is inside the cap, then secure the exposed end with a bolt and nut.
- If you have hot glue, use it to seal the drilled hole in the cap. This will also keep the line in place and ensure a reliable vacuum seal.

Load the bottle with Airsoft pellets. Filling it about halfway works best for optimal performance.

Secure the barrel and connect it to an air compressor. Make sure everything is tightly sealed before attaching the blowgun base to the air compressor.
- If you prefer, you can also use a backpack air supply to power your homemade gun.

Time to fire! Your gun is now ready for action. Simply unscrew the barrel to reload it with pellets as needed.
Precautions
- Never inhale any BBs!
Items You'll Need
Simple & Fast Method
- A small container with a lid (e.g., a medicine bottle, a 35mm film canister, a small soda bottle, etc.)
- 5/16" drill bit and drill
- Hot glue gun (optional, for extra sealing)
- A basic straight-ballpoint pen
- Airsoft pellets or BBs
Using an Air Compressor
- A soda bottle with a cap
- 1/4" quick-release air compressor adapter
- Drill
- Blowgun for air compressor
- 7mm x 6" brake line
- Airsoft pellets or BBs
Related Topics
- How to Create an Airsoft or BB Gun Target
- How to Craft Airsoft Weapons
- How to Load an Airsoft Pistol
- How to Select the Right Airsoft Gun