Spring Powered BB Gun

This is a project i am currently working on - spring powered BB/Dart gun. Requires Spring, Metal/PVC pipe (Whichever you feel more secure with, i chose metal), Metal barrel, I chose 4.5mm .77 barrel from an old airgun, spring, some cutting of wood, and dowwel. This is alot more powerful than other bb guns powered by combustion, bike pumps ect. so be carefull.

Step 1: Materials

Airgun Spring - Check your local airgun shop, or if your australian, find one.

Wooden circles, cut with a hole saw

Metal tubing, to fit your spring.

Endcap for the tubing

4.5mm copper, or any other metal tubing for barrel, 4.5mm is .177 for metal bb's or airgun darts, although if you wanted to fire plastic bb's you will need 6mm tubing i think.

Metal dowwel

I think thats it *thinking face*

Step 2: First Step (not Really Step Two)

See picture, you only cut into one side of the piping, dont go all the way through

Step 3: Step Two

Add your spring to the tube

Step 4: Step Three

Now, put a holesaw on your drill with 4mm drill bit in and whatever holesaw bit you need to fit your spring tube, it has to be able to move in there, if need be file it down a bit if you dont have the right drill bit.

Then, throught the hole in the middle, glue the 4mm dowweling in.
Screw a screw in the top of your circle, the slide the screw down your cutting in the springtube, therefore compressing the spring, and then twist to the side, locking in place, this is how you cock your gun.
Put this in your spring tube.

Step 5: Step 4

Now copy step three, but put a 4.5mm drill bit in your drill with a little larger holesaw bit, this shouldnt move in the spring tube. drill your circle out.

INstead of dowweling use 4.5mm (hollow!) copper/metal pipe do not block it off at all, this is your barrel

Glue the hole thing onto the other end of your tube, like an endcap. all done:)

Step 6: Tripple Barrel and Body.

Triple Barrel

The picture below shows how to add tripple barrel, just change step three, drill three holes in the wooden circle and put three pieces of dowwel in, also, change step 4, to 3 barrels

Body
For the body, be inventive, it all depends on the size of your spring/spring tube, mine is going to be around 16" i think so i am going to build it as a sawn off shotgun.

Convert to real gun

Ok, i think this would work, as it is basically a much more powerful zip gun (powered by elastic band).
You sould just be able to sharpen off the metal dowling with a dremel/file, until it is about as sharp as a sharpened pencil.
Change the barrel to whatever size bullets you want it to take ...8mm, 9mm .22, whatever.

I havent tried doing this but i think it would work.

Any questions or comments please email-: [e-mail]
I have a website coming soon.

Comments

[Sgt.Waffles]

As an amatuer gunsmith, i can see several flaws in this design. 1. The caliber for a standard bb/pellet gun is .177, not.77, which is larger than the standard paintball,(.68) 2. you need to get rid of all of the wood in this project. have someone maching you a circle, and use stock steel for the dowle. 3. In order for the screw to properly hold the weight of the spring, it must be perfectly balanced. Hope it helps. i look foward to seeing a finished project.

[Fryface36]

Thx. I'll keep that in mind, while making this.

[Srg.Snipe]

Huh? As you beeing a gunsmith, I dont think your the greatest.... Why would you say that the nail should be steddy, When it supposed to go in the wood... nOt the spring.

[Sgt.Waffles]

Well, bashing someones trade because you cant read sounds quite silly now doesnt it you dolt? It needs to go into the wood (which should be replaced with metal) and if it is off center even a little bit, the wooden circle will become cockeyed. Understand better now?

[omniusefull]

I want to shoot 1 in. Ball bearings at 550fps(could be a little less but no higher, very important legal stuff), what kind of spring do I need and how do I calculate it, I've got some knowledge in physics.

[indiana_j lol]

Where is the trigger?

How big does the spring have to be

[takn37]

it has no trigger you just pull back and let go............

[bigman123]

cool gun ! where is the triger

[sabladask]

Good! see my instructable i made a springpowerd piston airgun.

[Surefire123]

Sorry Scoblania but momentum is not force x time that's impulse which is the change in momentum over time. Momentum is Mass x Velocity. So you need to increase the impulse of the ammo.

[scoblaina]

i really do like this design, and currently using three really strong springs 9cm by 3.5 (bought in bunnings, yes im aussie) and so yeah its pretty big, but while it has immense power, shoots really badly (using thick nails cut in half and so are about 3.5 cm long, they should be solid enough yet aerodynamic enough so i dont think its the ammo) anyway i think the trouble is that its not providing enough momentum, as the steel rod only pushes the nail about 15cm, before the nail relies on its own momentum. Because change in momentum=force x change in time, i think that the rod should push the nail for a lot alot longer (maybe even 50 cm), so is in contact with nail for longer, but this means a lot more springs which means the whole thing has to be bigger (think of how far you pull back a slingshot), so i recomend if having a fairly big powerful design make sure the rod is long, i will keep working on this and let you know what happens

[Evidenceremoved]

Go Australia! Go Bunnings!

[guitarwizard94]

Has anyone actually made this? If not I have a few ideas obviously majority credit going to Camster911 but I'll think of a design!!!! Using a BIC Pen and a BIC Lighter!

[scoblaina]

yeah it should be pretty good and il work on the ammo problem. il probs have it finished in about 3-5 weeks when i have more time and il keep this page posted when im done with links n stuff, it should be pretty big though

[owen95]

thats cool cant wait to try it.    but first up scoblaina the nail is not the right sorta ammo to be shooting , a pellet or bb is much smaller and lighterand a bb ofers better acuresy then a nail "out of a smooth bore"

but yeah i cant wait to try it hope u dont mind me tryin to modify ur disign to go in a stock with a trigger.

[JACK_MAN64]

hey umm yer im with smily face im an ausse so how the hell do i find one like were do i go to get one your great ps i did it and its awsome but it took me about like three months to get a spring that was good

[Rikufan12345]

i made the gun and it sucked, the bb only shoots like five yards . . . . . . . . . . . idk maybe it's the spring?

[Camster911]

By The way, in all this pictures the gun is upside down to show you how to mkae it, the screw should be under it. You pull it back, twist to the side, and aim, and press with your finger sideways to fire. :)

[liquid008]

how do you make the gun hold the BB in place when you cork the gun before shooting? Because I am making a bb gun out of a toy gun as it has the basic shape. There will be a lot work to do. In Singapore any form of bb guns is illegal and will be charged in court for owning a fire arm.

[Madrias357]

Agreed. In America, we can build our own guns. I couldn't imagine not having at least some sort of BB gun laying around the house. I have 2 custom ones (one's broken, the other half-finished), several hand-made rubber band guns (a dual-shot rifle, a simple pistol (instructable on it), and a bigger one designed to shoot high-power rubber bands.), and other assorted weapons, including a few airsoft guns, and some of my projects.