Introduction: 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

Comments

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ThisGuyLovesToBuild made it! (author)2017-04-13

Is there anything i can use to substitute the brake line?

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CigarSmoker2 made it! (author)2016-02-19

So I made one this morning using a root beer bottle and a hard plastic straw that was the right size for the bb's, and of course my air compressor. Even with the scavenged parts, this is SO MUCH FUN!!!! Thank you.

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4086449 made it! (author)2015-12-18

I made this gun for my airsoft loving friends birthday. I put 2 guns on a camera tripod. It was by far the best gift. Thank you for this great instructable

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AlexanderM11 made it! (author)2015-07-16

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?

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AlexanderM11 made it! (author)AlexanderM112015-07-17

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

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techsean made it! (author)2012-02-16

I love this and will build with with my nephews . Thanks for helping to get them excited about making things.

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NightHawkInLight made it! (author)NightHawkInLight2012-02-16

I love to hear people wanting to help kids get into creating things. Have fun! Don't forget the safety glasses!

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AlexanderM11 made it! (author)AlexanderM112015-07-16

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

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techsean made it! (author)techsean2012-09-06

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

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RavenX185 made it! (author)2015-01-20

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

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AlexanderM11 made it! (author)AlexanderM112015-07-16

go to a hardware/auto parts store

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JohnG23 made it! (author)2015-02-10

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

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ewkabel made it! (author)2015-01-19

will it take down pigeons?

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wheelerphoto made it! (author)2015-01-15

We can't find a straight


  • 7mm x 6" Automotive Brake Line
  • online, any ideas on how to get one?
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steven.kettles made it! (author)2015-01-07

awesome post!.

I am working on a diy shotgun at worldpremierairsoftcenter.com

also doing a diy sniper rifle and bunkers = )

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surya.navet made it! (author)2014-10-20

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

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surya.navet made it! (author)2014-10-20

it is epic

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tonroh17 made it! (author)2014-02-18

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

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Sludgeman101 made it! (author)2013-08-10

If i used a co2 bike pump and plugged it into the blowgun in replacement of the air compressor, would it work?

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thaspil made it! (author)2013-06-18

If you used a longer sized bottle, would you need a longer sized brake line to accommodate?

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ninjabuilder12 made it! (author)2013-04-10

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??

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black_lotus1232 made it! (author)2012-10-19

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

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XxsonicxX made it! (author)2012-08-11

WHERE DO YOU BUY THE BRAKE LINE? D:

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shadow_malakai made it! (author)2012-07-11

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!!!

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Radioxi made it! (author)2012-06-16

Here's an idea: Take a pump and a small air tank, combine it with the air switch and bottle- voila! - DIY airsoft shotgun.

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lzabadiel made it! (author)2012-05-23

nice. like the guns in the game fallen earth.

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kilroy00 made it! (author)2012-05-13

Using your design I modifed an ammo box to build a Browing M1919 thanks for the idea.

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erfinder made it! (author)2012-05-01

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?

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NightHawkInLight made it! (author)NightHawkInLight2012-05-01

Yes, that will work.

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erfinder made it! (author)erfinder2012-05-01

In your backpack airtank video was the shooting shown all the tank could manage?

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mayday12 made it! (author)2012-04-02

i mean NightHawkInLight. ("") (*<*) ("")

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NightHawkInLight made it! (author)NightHawkInLight2012-04-02

Thanks! Good to hear

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mayday12 made it! (author)mayday122012-04-02

I'm using a tank i bought online for the air supply. (3 gallons)

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mayday12 made it! (author)2012-04-02

I must admit, i am a HUGE fan of your work.

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mrpesas made it! (author)2012-02-22

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.

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Jarheadicus made it! (author)Jarheadicus2012-03-21

or you could try and add some kind of hopper on, say, the top of the bottle when holding it in firing position.

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NightHawkInLight made it! (author)NightHawkInLight2012-02-22

If you bend the brake line it will change shape around the curve and the pellets will no longer fit through it.

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hedzup456 made it! (author)2012-02-14

Dude, what is in that target!?

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NightHawkInLight made it! (author)NightHawkInLight2012-02-14

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..

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hedzup456 made it! (author)hedzup4562012-03-03

I like it. Might steal that idea for my Knex guns, when im showing them off to my mates!

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Matthajek made it! (author)2012-02-28

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.

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bluerogue made it! (author)2012-02-24

awesome ^^
i am new to this site and i have a little problem where to get the break line is it in carpenter or ........

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NightHawkInLight made it! (author)NightHawkInLight2012-02-25

It's a brake line, not break. They can be found in any auto parts store.

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bluerogue made it! (author)bluerogue2012-02-26

thank you but is there any place other than auto store

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triciab1212 made it! (author)2012-02-24

Awesome!! Saw this vid first on Right this minute on national tv !!!!! When i saw it, i was thinking..."hmmmm that's such an Intructable kind of project"!! and i was right!! too cool!

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NightHawkInLight made it! (author)NightHawkInLight2012-02-25

Sure enough

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pyromanic made it! (author)2012-02-24

have you tried puting more than one barrel on the front so it can shot more

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HollyMann made it! (author)2012-02-20

My 7 yr old son is FASCINATED...awesome instructable.

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NightHawkInLight made it! (author)NightHawkInLight2012-02-21

Why thank you

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nuketz made it! (author)2012-02-20

Instead of the Brake Line, would it be possible to use an actual barrel from an airsoft gun? Or is the clearance that the Brake Line provides necessary for the BB's to get sucked through?