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Build your own BB machine gun


BB machine gun, printed book

Price: $39
Pages: 83
ISBN: 978-91-633-6173-9
Published: 2011

Shipping cost: $12 flat rate
worldwide shipping

BB machine gun, printed book with key component kit

Price: $49
Pages: 83
ISBN: 978-91-633-6173-9
Published: 2011

The key component kit includes:

- 6-9V electric motor
- Axel adaptor
- Oversized worm gear with a
matching 30 tooth radial gear

Shipping cost: $12 flat rate
worldwide shipping

BB machine gun, e-book

Price: $18
Pages: 83
ISBN: 978-91-633-6173-9
Published: 2011

You can download the e-book as soon as your purchase is completed.

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This DIY compressed air BB machine gun is designed with DIY-ability as priority no 1. No exotic materials are needed except for the nylon gears that comes with the key component kit. The tool requirements are also modest, a drill press is the only expensive machine you really need, although a router, belt sander and a lathe make work easier, they are not necessary in order to achieve a good enough result.

This build results in a quite powerful electro-pneumatic BB machine gun. The machine gun is based upon a 2 kg fire extinguisher canister. The compressed air held by this canister is enough to empty the built in magazine, which holds approximately 90 steel BBs, 1-3 times over depending on the pressure you are able to achieve when filling the canister.

With an ordinary bicycle pump (9 bar) you can reach velocities of 133m/s (436 fps). If you fill the air canister up to its maximum rating, in this case approximately 16-18 bar, the BBs velocity reaches 180m/s (590 fps).

The rate of fire depends on how accurate your build is and your systems voltage. The machine gun shown in this build has a rate of fire in between 300-500 rounds/min at 7.2-12 V.

The machine gun is designed around K&S brass tubing. There are two good reasons for this; their 7/32 brass tube has a inner diameter suitable for 0.177 BBs and the 7/32 tubes outer diameter is a perfect sliding fit inside their ΒΌ brass tube, which is very convenient in this design.

One of the best things with a BB gun using compressed air as a source of power is that refilling the canister is virtually free.


amazingdiyprojects.com / the author / inventor will not be held liable for any material losses, injury or death resulting from information used in this book to construct any part of an air gun. Building and / or using this product is done entirely at your own risk. Each country has its own laws regarding air guns. Please learn and obey the laws in your own country.


  • Specifications
  • Exploded view with named parts
  • Step-by-step building instruction
  • List of materials
  • Where to buy materials online

Look inside

Inspirational videos

Recreational target shooting.


Shooting over water.