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video Make an Airsoft Machine Gun from a Soda Bottle
Several months ago I posted a project showing how to make a 'cloud' BB machine gun with a built in air supply out of PVC. That project, while very entertaining, cost $50 in parts and took several hours to complete. More recently I have resumed experimenting with BB machine gun designs with the goal of making them as inexpensive and easy to build as possible. The model that is made in the above video can be assembled in under 5 minutes, uses only four parts, and costs a total of about $15. If you have not seen my previous BB machine gun project you can take a look at it by clicking This Link.

This airsoft gun is a bullpup design, meaning that the pellets enter the barrel from behind the trigger. The machine gun works because as the bottle is pressurized the only way for the air to escape is through the barrel. That escaping air sucks pellets up and out with it like a high velocity vacuum. The rate of fire that can be achieved through such a design is spectacular, in excess of 50 rounds per second. The estimated FPS using a 6" long barrel is 250 when the bottle is fed with air at 100 PSI. If a longer barrel is used much higher velocities can be achieved.

Parts Required:
  • Soda Bottle
  • 7mm x 6" Automotive Brake Line
  • 1/4" Quick Release Air Compressor Fitting
  • Air Compressor Blow Gun

Tools:
  • Drill & Drill Bits
  • Hot Glue Gun
  • Air Compressor

The only downside to this particular machine gun is that it must be plugged directly into an air compressor line to fire. Fortunately, there are several modifications to this project that remove the need for a constant connection to an air compressor, such as a backpack mounted air tank. A flamethrower style backpack tank version will be featured in my next video, in addition to a modification that requires no access to pressurized air whatsoever, and will cost even less than the featured model.

Please remember as always to share this article with others on Facebook and Twitter, and if you really want to support my projects, submit this article to other sharing sites sites such as Reddit and Digg. To be the first to know about my new projects you can also subscribe to my YouTube Channel.

Until next time,
-NH
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I'm doing something similar- I'm just using canned air instead of a compressor so I can easily take it to wars. My main worry is how long the gun will last before it breaks due to wear-and-tear. Should I reinforce it with wood to keep it functional, or should I remake it, but use pvc instead of the bottle?

just finished it- thanks Nighthawk for the instructable! I'll post one of my modded ones here :)

techsean3 years ago
I love this and will build with with my nephews . Thanks for helping to get them excited about making things.
NightHawkInLight (author)  techsean3 years ago
I love to hear people wanting to help kids get into creating things. Have fun! Don't forget the safety glasses!

NightHawk- I'm wondering as to the placement of the air blower. Does the position matter? Thx

We did use the safety glasses and it worked out fine.
RobbieC17 months ago

Um, would you possibly be able to post a link to where you got the blowgun? I cant find that type anywhere...

go to a hardware/auto parts store

JohnG236 months ago

Awesome toy! I couldn't wait for the auto parts store to open, so I substituted the brake line with a 9/32 brass tube 12" long (K & S part #132). I used a plain rubber grommet to hold it in place....no glue required. These are available at most Ace hardware stores and/or hobby shops. If you think about it, the air pressure is only acting on the surface area of the end of the tube to push it out....a very small area. The most ingenious part is that the incoming air agitates the ammo and keeps it feeding the barrel....no bends needed. I rigged up a leftover Ballon Time helium tank for the air supply. I had to drill out the check valve to get it to accept air....great fun!!! I found the blow gun at Harbour Freight. This a great harassment tool for predators.

John

ewkabel7 months ago

will it take down pigeons?

wheelerphoto7 months ago

We can't find a straight


  • 7mm x 6" Automotive Brake Line
  • online, any ideas on how to get one?

awesome post!.

I am working on a diy shotgun at worldpremierairsoftcenter.com

also doing a diy sniper rifle and bunkers = )

surya.navet10 months ago

tried it on my friends it worked like hell...... :)

surya.navet10 months ago

it is epic

tonroh171 year ago

Made it and it works like... like... like a bought one!

If i used a co2 bike pump and plugged it into the blowgun in replacement of the air compressor, would it work?
thaspil2 years ago
If you used a longer sized bottle, would you need a longer sized brake line to accommodate?
Would this still work if I made a hole in the back and put my blowgun into the hole at the back of the bottle??
great build. Do you have any ideas where to get the parts though bunnings ,auto place?? i'm not sure if not do you know any other parts you could use as replacements easier found. Thanks
XxsonicxX3 years ago
WHERE DO YOU BUY THE BRAKE LINE? D:
I got an idea for a more portable supply. No doubt a lot of viewers who watch this also play paintball, like me. If they have a 48ci 3000psiCompressed Air/Nitrogen Tank or better, they could hook up their feed line to the compressor blower tool. Most people who play with Compressed/N2 air use waistband or backpack harnesses with a slinky hose running to the gun. Just more ideas... LOL.... Have fun guys and remember safety first!!!
Radioxi3 years ago
Here's an idea: Take a pump and a small air tank, combine it with the air switch and bottle- voila! - DIY airsoft shotgun.
lzabadiel3 years ago
nice. like the guns in the game fallen earth.
kilroy003 years ago
Using your design I modifed an ammo box to build a Browing M1919 thanks for the idea.
erfinder3 years ago
I had an idea, what if I used pvc instead of the pop bottle and made the gun look however I wanted. Would it still work do you think?
NightHawkInLight (author)  erfinder3 years ago
Yes, that will work.
In your backpack airtank video was the shooting shown all the tank could manage?
mayday123 years ago
i mean NightHawkInLight. ("") (*<*) ("")
NightHawkInLight (author)  mayday123 years ago
Thanks! Good to hear
I'm using a tank i bought online for the air supply. (3 gallons)
mayday123 years ago
I must admit, i am a HUGE fan of your work.
mrpesas3 years ago
A couple of ideas came to mind after watching. Could you bend the brake line so that it feed from the bottom of the bottle? This might improve the total number of bb's you can shoot before needing to reload. Also, you could replace the brake line with a stiff hose or plastic tube, if you could find one just the right size.
or you could try and add some kind of hopper on, say, the top of the bottle when holding it in firing position.
NightHawkInLight (author)  mrpesas3 years ago
If you bend the brake line it will change shape around the curve and the pellets will no longer fit through it.
hedzup4563 years ago
Dude, what is in that target!?
NightHawkInLight (author)  hedzup4563 years ago
It's corn starch sandwiched between aluminum foil and the cardboard box. I have it in there to give a better effect when the pellets hit..
I like it. Might steal that idea for my Knex guns, when im showing them off to my mates!
Matthajek3 years ago
I made one that uses a 2-Liter bottle and a ball pump connected to the original bottle instead of a compressor or backpack, and it's light, stylish,and very functional! You hold it like darth maul's lightsaber; the "blowgun" (nozzle) is between the two.
bluerogue3 years ago
awesome ^^
i am new to this site and i have a little problem where to get the break line is it in carpenter or ........
NightHawkInLight (author)  bluerogue3 years ago
It's a brake line, not break. They can be found in any auto parts store.
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