Instructables
In this instructable I will be showing and describing how to build your own 700fps BB gun inside a metal flashlight. These are relatively simple and cheap to make and require basic tools and a little know-how. These BB guns are not intended to be shot at people; they are far too dangerous and will easily cause permanent damage to an eye.

New how-to video:


For this Instructable you will need:
1 x metal flashlight
1 x 6mm brass tube (or similar metal tube that fits a 6mm BB)
1 x schrader (tyre) valve - it can be threaded, ripped from a bike tube or be one of those rubber tubeless snap-in ones
1 x  JB-Weld, araldite or similar epoxy
1 x superglue
1 x bike pump or CO2 inflator or air compressor

Tools:
Hack saw
Drill
Hot glue gun

Click HERE for an animation on how it works.

There are a few small bits and pieces that may be required but they can generally be found around the house, in the garage or can be bought for cheap at a hardware store.
 
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Step 1: Finding the right Flashlight

For this build you do not need an expensive Maglite or branded flashlight, the most important feature of the flashlight is that it has to be metal. The next important part is that it has a threaded cap on the end for changing the batteries; this cap must also be made of metal and it should have an o-ring around it so the seal is watertight. The only other requirement really is that the flashlight has the push-button/switch to turn it on mounted in the end cap, if the on/off button is mounted on the side of the body then the flashlight can't be used for this build as we intend to use the flashlight body as an air tight chamber.

Flashlight check list:
1. Flashlight is all metal.
2. Flashlight has a threaded cap for the batteries - this is required so the valve of the gun can be removed from the gun in case it stops working
3. Flashlight has an end-mounted on/off switch and not a switch mounted in the main body.
4. Flashlight body is a cylinder and not some weird shape; e.g. a conical cylinder that tapers at one end (this does not include the flared end that houses the light bulb as this can be removed and is not part of the flashlight body)


So those are the basic requirements; most metal flashlights should meet these requirements. The silver flashlight in the picture above meets most of these requirements as it has a threaded end cap with an o-ring, is made of aluminium and is a perfect cylinder. Although not visible in pictures below, this flashlight actually has a push-button mounted in the body of the flashlight and not the end cap, this means this flashlight cannot be used as it will have a big hole in the body once the components are removed. Apart from that, it is a good example of the type of flashlight required.

The green 'Kathmandu' flashlight above shows a picture before modification and a picture after it has already been modified in to a BB gun by myself. It is another good example of a flashlight required for this build: metal construction, threaded end cap with o-ring, cylindrical body and end mounted on/off switch (it has been replaced with a schrader valve in the photos below).

dos it matter if bike valve ?

to pump it up. will a electric car pump do the trick?

abauer63 months ago

Hey actually I'm trying to build one... I got milling and lathing machines at work and would like to send you some pictures of it and would like to ask you what Ur thinking about the takeable pressure of my build

MrCrowley (author)  abauer63 months ago
I'm no engineer so can't comment specifically on the pressure rating of the pipe or materials you are using. However, if you're using 3mm steel pipe you're going to be safe with pressures around 300PSI.

Keep in mind, this is the golden rule: your design is only as strong as its weakest part.

You can have 3mm steel pipe but use a plastic joint for something and that plastic will determine how much pressure your design can take. So, if you're using metal for every component, you're probably going to be safe with pressures around 300PSI.

The parts that hold pressure in my design are: torch body, epoxy plug, threaded end cap, schrader valve. The torch body is 2-3mm thick metal so should be safe for more than 300PSI, an epoxy plug at such a small diameter can probably take 600PSI+ without problem, the end cap is threaded but still fairly strong so 300PSI+ should be fine, and schrader valves can take well over 500PSI.

That should mean my design is safe for at least 300PSI. However, I wouldn't want to go over that too much. I can't comment on how much pressure your design can take without more detail, can you upload an picture?

Bist du Deutscher?
abauer6 abauer63 months ago

I'm using a 3mm steel pipe except of an torchlight and gonna weld the barrel side and solder the barrel into the hole on the Ventile side I got a costume made fullsteel screwing plug with like 10mm to screw in and an rubber ring im still thinking about the Ventil how to bring it into my costume made screw plug

gemoney5 months ago
can I use a short copper barrel with the same ideas but make this like a life size shotgun
linzhangyuan5 months ago

hi, i would like to build this bb gun, but i was wondering if the size of the flash light matters and if i can use a Maglite solitaire for the gun.

Sto1236 months ago

Hi Mr.Crowley,

I hope you can find time to answer this.

Some friends and I were trying to build a BB Flashlight based off a video from a guy name KipKay. What ended up happening is that there was some kind of design flaw associated with it and we ended up wasting about $70, we feel really stupid about it. We are hesitant to try this again since we only have so much money for ourselves. We would be willing to try this again, now knowing someone with your knowledge and experience could help us. The best way we could helped is if you can give us like an exact list with all the parts we need, what there dimensions are, where do get the stuff, and the exact brands associated with the parts --- we plan to copy exactly what you did word for word, using the exact parts that you used.

Thanks

Pullsee11 months ago
If the piston is a good fit, how does the air get from the pilot volume to the main chamber (when u filling it up)? Is it just thru natural seepage? Thanks.
ilpug2 years ago
Well, this looks pretty awesome, but i have to read it a little bit more deeply to fully understand it. This is probably pretty dangerous, but that is probably part of the fun.
MrCrowley (author)  ilpug2 years ago
If you have any questions about the instructable or you think something needs further explanation; please let me know as I published this in a hurry so I could get some feedback on how to make it better.

It can be quite dangerous but safe when operated correctly. I will add another step dealing with handling and use and safety of this instructable so no one gets hurt.
my name is kevin and I live in grand cayman i love what you did to the maglite can you send me the info on how you made it.
i have made my own weapons in the past but not like this.... would love for you to help me make it and the triger part that you push many thanks take care.
can the piston be .75 cm without a hole in the middle because my gun wont work
white_phox1 year ago
Did you get this from KipKay?
MrCrowley (author)  white_phox1 year ago
Haha no. I made this literally years before KipKay did. This instructable itself is older than the KipKay video. I first made the cannon back in 2010 or something.
This is the instructable that got me going with my project, which is a "take down air gun" which is about 1/3rd of the way so far. Thanks bro, very good stuff and very clear explanations.
Hello there,

I have got brass barrel with 6mm outside diameter and 5mm inside diameter. Can I use 4.5mm pellets? Will it become too loosely?
Hey, I live in New Zealand and I wanted to know what exact flashlight you used
Thanks
Johnhall441 year ago
Do you know where I can get a 4.5mm barrel at,so I can shoot normal pellets?
Oww?
IML3ATHAL2 years ago
Is there a way to download the PDF with out having a pro account?
Try adding ?download=pdf   To the url. But you didn't hear that from me.
MrCrowley (author)  IML3ATHAL2 years ago
Not sure, I wasn't even aware I was a pro member myself.
IML3ATHAL2 years ago
Is there a way you could put the PDF download on a different lime mediafire?
MrCrowley (author)  IML3ATHAL2 years ago
here you go:
https://rapidshare.com/files/1977035125/700fps-BB-gun-made-from-a-Flashlight.pdf
IML3ATHAL2 years ago
can i use a 4.5 mm barrel so i can use 177. pellets?
MrCrowley (author)  IML3ATHAL2 years ago
Yeah it'll work fine
ballistic knife
patron_zero2 years ago
This is so Q-Branch-meets-MacGyver it's not funny, applause and kudos !
monsterlego2 years ago
Ha! nice.