3D Printable Airsoft Gun

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Introduction: 3D Printable Airsoft Gun

About: I'm a design engineer, and I invent and build machines and products for a living down in humble New Zealand. I'm addicted to the process of imagining parts, designing them, and seeing them materialise through …

PURPOSE

When 3D printers started to dramatically drop in price and were thrust onto the commercial market, I was immediately hooked. This is every engineer's dream come true! The storm of cool printable products really hasn't developed as I expected however. Most people were, and still are, only printing little sculptures and vases. In terms of pushing this technology to its potential, we're not off to a great start! I came to the conclusion that it is not a lack of vision that is limiting the use of these desktop printers, but a lack of designs. People would print more awesome things if there were more awesome things to print. So I put two and two together and started designing this printable airsoft gun. It's the start of many designs I hope to produce for people who really want more than just a vase from their printers. I hope it will inspire you to get your creative mind in gear and contribute some awesome designs for a 3D printable future!

TOOLS

  • 3D printer (I used an UP PLUS)
  • epoxy glue (and solvent if you have it)
  • screwdriver
  • drill (optional)
  • pliers
  • wire cutters
  • hacksaw

MATERIALS

  • 820g of ABS (just under 1 reel)
  • nuts and bolts $10
    -M3x16mm (qty. ~20)
    -M4x38mm (qty. ~15)
    -M4x25mm (qty. ~10)
    -M5x75mm (qty. 1)
    -M8 threaded rod (1m length)
  • 1m of 15mm OD metal tube $10
  • bike pump $4
  • spring $8
  • Airsoft barrel with bucking (approximately 350mm long) $15
  • spray paint (optional)
  • small scrap of 20mm PVC electrical tube
  • 2 or more ball point pens (dead or broken)
  • 7mmOD irrigation tube
  • 2x Old couch springs or other extension springs

GUN SPECIFICATIONS

  • Shoots 6mm bb's (0.2g recommended)
  • Single shot springer (spring powered)
  • Chronoed at 250fps with 0.2g bb's
  • Accurate to 20m, extreme range 40-50m
  • Weighs a nice 1.2kg
  • Mag capacity: 11 rounds
  • Picatinny rails
  • Adjustable hop up
  • Working safety
  • foldable bipod and sights (for scope if desired)

DISCLAIMER______________________________________________

I take no responsibility for your actions with this gun if you should decide to make it, or if you are not legally allowed to own such a gun according to the laws of your country and yet still decide to make it. This is an airsoft gun only, not a firearm, however it can do damage if aimed at the wrong place. Treat it responsibly and use the appropriate safety gear.

That being said I do encourage you to have fun! That's what this gun is for after all.

_________________________________________________________

Step 1: PRINTING

First things first, parts need to be printed and cleaned.

You will need just about a whole reel of ABS plastic (820grams). Haven't tried PLA, it is significantly weaker, but you can try if you want!

Most of the 46 parts will fit within the print volume of a desktop printer (120mm cubed), but there are a few larger parts that will need to be printed on a larger printer with 200mm width/depth and 200mm height. This is inconvenient I know, my next gun will be designed fully for a 120mm cubed print volume. You could split them and fuse them back together with solvent, but be careful about printing too large on an open bed, you may get warping.

The parts are all designed to be printed in a certain orientation for minimal support material, strength in direction of the forces, and also to prevent layers grabbing between parts, i.e. layers are perpendicular for fast moving parts.

Most of the pictures explain the assembly well enough, but I will comment on the design details as we go. If you're confused at any point, have a look at the exploded view animation to see every nut and bolt put together.

Step 2: BOLT

As you will have seen, the piston is actually a bike pump, simple and very cheap, it also comes pre-greased, so no need to look for some silicone grease.

Here's a couple of links to a similar bike pump:

https://www.ebay.com/itm/Mini-Bicycle-Pump-Portabl...

https://www.aliexpress.com/item/32973595341.html?s...

https://www.aliexpress.com/item/32963284075.html?s...

[Links last updated: 15th Sep 2019]

The bike pump needs to be roughly 28mm in diameter to fit in the upper receiver. As you can see, there are two main types of bike pump- cups and o-rings. O-rings give you a better seal at high speed, so get one of them if you can.

The cylinder head should be glued (using epoxy) into the bike pump cylinder which you'll have cut to 68mm long, then the piston head and catch should be glued to the PVC tube which you'll have cut to 72mm long. A 30mm long section of 7mmOD irrigation tube can then inserted into the front of the cylinder head. Finally, bolt the handle into the side of the cylinder head, and voila! Your bolt is complete.

Step 3: TRIGGER BOX

You'll need to savagely rip open a few dead pens and harvest their springs for use in the trigger box and hop unit.

The trigger box can now be put together using those springs, parts you've printed, and a few small bolts (15mm long 3mm diameter thread, and 28mm long 4mm thread).

If you want to know how it works, have a look at the 'Inside the 3D Printed Airsoft Gun' video, towards the end it takes a look at the trigger box assembly and mechanism.

Step 4: MAG

Now to assemble the mag. You'll need to scavenge a mag spring from a broken bb gun mag. I realise this is not commonly found, so in my next design the mag will use a rubber band which is much more easily available. You'll also need a few bobby pins, one of which you'll need to cut down to fit the grove near the top of the right side of the mag housing.

The humble bobby pin is actually made from high tensile spring steel, and makes a great spring for a mag catch, or for any other mechanical parts with a relatively short range of motion.

The function of the mag catches are to hold the mag into the mag well, which can then be pushed in, releasing the mag, by the mag release buttons on either side of the lower receiver.

Another catch sits up the top of the mag housing beside the channel for the bb's. This bb catch holds the bb's in while the mag is being loaded. When it is pushed into the mag well, it is pushed back out of the way by the feed tube that protrudes down about 5mm, allowing the bb's to jump up into the hop unit. This accounts for the satisfying click you'll hear as the mag is pushed in.

Unfortunately the gap between the top of the mag and the chamber means about 4 bb's fall out when the mag is removed, so the mag capacity is actually 15, but 4 don't make it into the chamber unless you tip the gun upside down as you cock it. But this is a minor problem most airsofters will have come across before. In my next design however, I will fix this issue with a more realistic loading style where the bolt carries a round up into the chamber, hence covering the vertical gap.

EDIT 06-10-18:

I've uploaded a modified mag that uses a rubber band rather than a mag spring as they can be difficult to obtain. Check out the zip file named 'Magazine Update- rubber band' which includes all the .STL files for printing, a few images to help you assemble it, and a .STEP of the whole assembly for those wanting to take a look inside- questions are welcome!

Step 5: LOWER RECEIVER

As previously mentioned, the lower receiver has two mag release buttons on the sides which are simply pushed into two holes inside the receiver. You may need to do some sanding if you can't remove the all support material inside the holes. When both are pressed, the mag is released and can be pulled out.

The grip is fixed in a similar fashion to real guns, where a bolt is inserted through the base of the grip up into the lower receiver. The vertical slots in the grip prevent any unwanted forwards/backwards motion.

Perhaps surprisingly, the trigger box is not actually fixed into the lower receiver. This is because when the upper receiver is bolted on top, it holds the trigger box in place. In my next design I am leaning towards an assembly with minimal fixtures and no tools required.

Step 6: UPPER RECEIVER

The lower receiver is now all assembled, we can begin on the upper receiver where the real action takes place! (excuse the pun)

There are two fixtures between the upper receiver and the lower receiver, one is a hinge at the front, and the other is a bolt through the baseplate and the stock. The hinge allows the guns internals to be accessed easily, the same idea as the ICS split gear box design.

You'll need to choose a spring now, I used an M130 second hand airsoft spring which cost me about $10 from ebay. You may need to snip your spring down to size so it isn't too pre-compressed.

The trigger must be held down to insert the bolt, just like a real gun. After the bolt

Step 7: STOCK

Time to attach the stock.

One bolt goes through the lower hole on the stock base to fix it to the lower and upper receivers.

You'll need to cut two lengths of 15mmOD metal tube, steel, aluminium, or even copper, doesn't matter too much. They then need to be glued into the shoulder rest as seen above. If you're spray painting, do that first before you glue so you don't have to tape around awkward angles.

One awesome thing about 3D printing: fancy cut-in design patterns actually reduce time and cost to implement, unlike conventional manufacturing processes where this would add cost and time. Less material, less time. It just makes sense!

Step 8: HOP

Moving onto the hop unit now. If you're not an airsofter, hop-up is backspin on the bb that allows it to travel further, the bb literally 'hops up' instead of dropping early. This unit presses a small rubber sleeve down into the barrel so that when the bb passes it, it catches slightly, giving it backspin.

This hop unit uses a slightly angled slide pushing a ball bearing (in this case, a bb) down onto the rubber sleeve so that the amount of contact between the bb and the rubber can be finely adjusted.

The chamber spring prevents bb's from falling back into the upper receiver when the bolt is pulled back and the nozzle comes out of the chamber, something I call 'backwash'. It was a really annoying design challenge as I wasn't willing to fix the cylinder in place and have to pull back the piston itself to cock the gun. But again the trusty bobby pin saves the day!

Step 9: FRONT UPPER RECEIVER

Now to assembly the front half of the receiver. You'll see a large threaded rod up top, this provides strength down the entire length of the gun, and bears the brunt of the force from the piston hitting the cylinder head, so that the plastic doesn't have to, making the gun very durable. But of course, if a part does break, just print another one! Gotta love 3D printing...

The pictures explain how to assemble the gun, but remember to cut another section of metal pipe however long you wish your barrel to be- maybe sniper, maybe assualt, whatever look takes your fancy.

You may be curious at this point as to the style of the gun. It is actually styled after a SCAR-H, obviously not the same, but it imitates the look and feel of the gun. Why the SCAR-H you ask? Just because I like the look!

Step 10: FINISHING TOUCHES

Finally we can add the icing on the cake, our rear sight and bipod. These are simple enough to put together once you've printed off the parts, so I'll leave you to it.

The rails are the same dimensions as a picatinny rail, weaver will also fit. I haven't tried a scope on it yet as I don't own one, but if anyone finds it doesn't fit, let me know and I can change the files.

Step 11: HAVE FUN.

There you have it, your own 3D printable airsoft gun. If this project is a little too big for you, stay posted for my next gun which will require less materials and tools, have more cool features and can be printed on a 120mm cubed desktop printer.

Hope you enjoyed the Instructable, whether just for inspiration, for actually making the gun, or just for a good read. If you were wondering how I got my printing done, it was through Palmer Design and Manufacturing.

A huge thanks to Andrew Palmer there for all his help with the printing. PDM does professional end-use parts manufacture or prototyping, there's some awesome stuff on the website, check it out right here:
https://palmerdesign.co.nz/3d-printing-quote/

I welcome constructive feedback and any design advice or ideas from you guys! If you've got some solidworks skills feel free to make some changes or additions to the files to keep improving them. Designs won't be sold for licensing reasons, so they're all yours!

Thanks for reading

Step 12: Accessories

Thanks to Roy-Tore Hofstad (rhofstad), the gun now comes with a foregrip and a flashlight holder! These accessories really make the gun intimidating. He also made a larger front sight to accommodate a thicker barrel.

Thanks again to Roy for modelling those up, and make sure you print them if you are making the gun!

23 People Made This Project!

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405 Comments

0
dumle11
dumle11

6 weeks ago on Step 4

Hello! First of all, thanks for the amazing work.

I am in the process of printing the parts for the rubber band mag and was wondering how should the rubber band be attached? In the .steps file, it looks like one end should be inside that little hole, but what about the other end that is floating in the air? Should both be connected to the same place? What about the size of the rubber band, are there any recommended ones that work best?

Thank You again!


rubber-bang.png
0
Benjovie
Benjovie

Reply 27 days ago

Your solution is in mag_right- V2.stl file.
The other side of the part you show here, you will see some sort of hook part where you can attache your rubber band to.

Screen Shot 2023-01-06 at 15.40.32.png
0
jasongilding222
jasongilding222

Question 4 weeks ago

Would it bee able to be modified to flip up the bolt to a 90 degree angle then pull back? And do you think the bike bump can push a 13 mm 3d printed projectile?

0
Benjovie
Benjovie

4 months ago

Thanks for the design, I've tried to push it to it's limit in term of FPS, I've been able to reach a reliable and relativity accurate 430~460 fps with 0.2g bb. For that I used a few modifications obviously.
I adapted the model to use a regular airsoft cylinder with head rather than the bicycle pump one. I designed then a new handle and an adaptor for the cylinder head to the handle. These i ordered a metal 3D printed version to support the constraints.
Also the hop unit assembly I changed to gain in effectiveness with the magazine and to avoid the bb running away in the chamber.
This modification also require a small metal 3D printed part. Maybe total 50$ ordered online. You will need equipment to sand down the metal part to a good fit, like a Dremel.
The spring is a M190 with maybe 2.5cm removed to fit.
The rest is stock and all printed in PLA+ but seems to hold well.
Example of barrel, piston head, screw for head cylinder and handle assembly, metal tube for hop unit, spring, cylinder, nozzle, bucket:

https://www.amazon.co.jp/gp/product/B0976PWGKR/ref...
https://www.amazon.co.jp/gp/product/B094X2CB3H/ref...
https://www.amazon.co.jp/gp/product/B07DK4VD5M/ref...
https://www.amazon.co.jp/gp/product/B07K56X75H/ref...
https://www.amazon.co.jp/gp/product/B085VSFPY5/ref...
https://www.amazon.co.jp/gp/product/B01N6N3BOZ/ref...
https://www.amazon.co.jp/gp/product/B07R496Q16/ref...
(used the 3/8" 3/4" spring from this box for the nozzle catcher assembly, you might need to trim it a little)
https://www.laylax.com/products/detail.php?product...


Also needed, https://www.amazon.co.jp/gp/product/B086QW2JHF/ref...
Will have to be trimmed to be used as a spacer between the cylinder head and the aluminum nozzle recommended above. Should be around 1cm, but grind it little by little until you have a tight fit with the barrel in the hop unit.

The 7mm metal tube is to be assembled with the hop bottom cover and a spring to push the nozzle catcher of the hop unit.

Of course doing all of that come to a cost, so it is not so much about saving the money than having fun designing and experimenting and having its own unique assembly.
I definitely don't recommend if you are doing this to save on money. Probably to source all part it could get close to $150 (unless you have parts lying around from a dead rifle).

0C147D51-283A-40D5-9BB3-55D1EF05C69E.jpegScreen Shot 2022-09-20 at 12.24.59.pngScreen Shot 2022-09-20 at 12.25.10.pngScreen Shot 2022-09-20 at 12.25.21.png
0
schmerzdj
schmerzdj

2 years ago

Airsoft isn't legal here and I'm not sure if I can get the barrels... Is there anything I can use in place of an actual Airsoft barrel? Will a tube work?

0
Engineer777
Engineer777

Reply 2 years ago

A brass or aluminium tube with an internal diameter of between 6.0mm to 6.1mm should work. Steel tube often has a seam that runs down the internal surface, causing the bb to bounce around and allowing more air to escape. The closer to 6mm ID the better, at 6.1mm you will find the gun is quite weak.

0
deleteduserdev
deleteduserdev

Reply 7 months ago

what about the spring? Where can I get a spring?

0
chris.a.tranovich
chris.a.tranovich

Tip 9 months ago on Step 1

For those of us in the US
M3x16 ~ 6-32 x 5/8” (3/4)
M4x38 ~ 8-32 x 1 1/2”
M4x25 ~ 8-32 x 1”
M5x75 ~ 10-32 x 3”

0
dudleycarlos81
dudleycarlos81

1 year ago

thanks for the hard work on this. I'm currently printing out the parts and looking forward to building it. just wondering if you would design the p90 or a ar15 any time soon. both fantastic guns and would be great to build them

0
JanK5
JanK5

Question 1 year ago

Hi, which side is better to print the lower receiver?

0
xXDeadRazeXx
xXDeadRazeXx

Question 1 year ago

Hi, i have few questions about outer and inner barrel.
1. Is it possible to use a longer inner barrel?
2. Did you make the outer barrel? If yes what size is it?

0
Engineer777
Engineer777

Answer 1 year ago

Hi there, yes the inner barrel can be longer- you will just have to cut a longer piece of tube for the outer barrel. The outer barrel is a 15mm OD (outer diameter) metal tube; I used copper tube but steel or aluminium would be fine too.

0
xXDeadRazeXx
xXDeadRazeXx

Reply 1 year ago

Thank for reply. Also one last question.
Would it be possible to use normal airsoft pump with cylinder instead of bike pump? I'm not sure how this system works but I'm thinking of making it as powerful as possible

0
Engineer777
Engineer777

Reply 1 year ago

Yeah you can use a proper airsoft cylinder. However, you'll need to modify the diameter of the cylinder head and piston to suit the internal diameter of the airsoft cylinder which is 23.8mm. I'd recommend getting an airsoft cylinder and o-ring as well. You will need to add a spacer to the outside of the cylinder to help it cycle smoothly back and forth in the upper receicer. Best of luck! Let me know how you go

0
3dpeter1
3dpeter1

Question 1 year ago

Hi, I have a question about the magazine spring. What are the exact length, wire diameter and outer diameter of the spring ? Thanks for helping me out ;-) 3D-Peter

0
maresd80
maresd80

Question 1 year ago on Step 1

I have a couple questions
1-Where I can get the outter and inner barrel?
2:What purpose serves the barrel spacer?

0
Engineer777
Engineer777

Answer 1 year ago

Sorry and your second question: the barrel spacer fits onto the end of the inner barrel and holds it centred in the outer barrel