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 throug...

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
  • 2nd hand airsoft barrel $15
  • spray paint (optional)
  • small scrap of 20mm PVC electrical tube
  • dead pens
  • 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 the link to a similar pump I used:

http://www.ebay.com/itm/Mini-Portable-Bike-Bicycle...

[EDIT: this link goes out of date quickly, so look in the comments for more recent links]

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: http://palmerdesign.co.nz/3d-printing-service/

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! 

7 People Made This Project!

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267 Discussions

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good afternoon. this is really, really cool. your hobby is interesting. I'll be waiting for a new gun. I wanna ask. where do you buy balls (bullets)?

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leonhardly

Question 13 days ago

Any reason you don't have the parts on Thingiverse? I would have found this a long time ago if they were, instead of finding it in a random youtube video.

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ArnoP8

Question 17 days ago

Anyone can send me a correct pomp link thanks

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Mehmet.1

Tip 25 days ago

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TahirA19

6 weeks ago

what should be the length airsoft barrel?

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Engineer777jiji toaster

Reply 3 months ago

As long as it stretches around the end of the barrel and has a grippy surface. The actual bucking is made from a soft silicone rubber which has the texture of a rubber band. If the 7mm OD tube doesn't work it looks like Camo77 found a solution with the vinyl tube!

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BrianH437Engineer777

Reply 6 weeks ago

Thanks for the replies guys,

I am still having a hard time tracking these parts down, do you know if anyone has tried printing them with flexible filament? I picked up a roll yesterday, I am going to play with it a bit and see if I can get some settings dialed in, once I do that, I will likely model these parts and give it a go.

to do this, I believe I need a 7mm od likely with a 5mm id tube that will connect to the bolt, I will take a measurement for the length later today. I am thinking 5mm ID simply because it will not allow for the BB to enter it. plus a 1mm wall should definitely prevent air from passing.

The tube that will work in the hop unit will have a 9.5mm od. the ID is where I have a question, barrel side I think it should be 7.8mm, slightly smaller than the OD of the barrel, but where the hop slide pushes the other bb to give it the backspin, what ID should it have there ideally? I am wondering it it would be a good thing to have that taper so that there isn't a "sharp edge" where it hits the barrel?

if this works I will definitely post the models for these, I am still waiting on some parts from aliexpress but I am hopeful to have the hop unit ready for when they arrive. thanks again for the awesome model!

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BrianH437BrianH437

Reply 6 weeks ago

Thinking about it a little more, there is a notch in the barrel, which means the barrel is suppose to but up against the bolt tube...IE the bb sits in the barrel when it is ready to fire...makes a lot more sense, so all I should need is a length of 7mm OD 5mm ID and 9.5mm OD and 7.8mm ID tube correct? assuming the flexible fillament will stretch around the barrel that is.

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Camo77jiji toaster

Reply 3 months ago

I used clear vinyl tube, around this size, cut it to length and put it in warm to hot water to make it easier to slide on... but my barrel is a carbon fibre arrow tube which is smaller diameter

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BrianH437Camo77

Reply 2 months ago

Hi Camo,

I've searched through the comments but can't seem to find a link to it, any chance this exists? I am talking about the hop up sleeve solution, as of later today I will have everything printed for this, then I have to wait for a bunch of the parts coming from the other side of the world.

measuring the ID of the printed part I am sitting at 9.5mm or so, I assume I would want my OD to be something similar to this?

Thanks in advance, I am super excited to get this going!

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Camo77BrianH437

Reply 8 weeks ago

Hi Brian, I just grabbed a few different sizes from my local Bunnings hardware, it’s fairly cheap, like a few dollars per metre, clear vinyl tubing in the gardening hoses irrigation section. But if you can get the right bucking material then do that. Like what Sam said the bucking is made from a silicone rubber which is softer and more grippy. Regardless of what you use, it is a wearable part and will need replacing over time

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htc_han

Question 8 weeks ago

Hi there,
I have difficulties of finding a 2nd hand airsoft barrel
Is there any recommendation about the specific size and length?
Thanks

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Ashlylong1990

Question 8 weeks ago

What infill did you use for 3D printing the parts? Thanks and amazing build!

4 answers
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Camo77Ashlylong1990

Answer 8 weeks ago

Hey bud, I made all my parts at 100% infill but you could do some at say 40% like the front receiver, the rails, stock maybe.. I think the lower and upper receivers should be solid as well as the plunger parts due to the high impacts and stresses. I used Esun pla+ Filament which is supposed to be 10 times stronger than normal pla. If your using stronger filaments you may be able to have less infill like carbon fibre nylons etc..

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Ashlylong1990Camo77

Reply 8 weeks ago

Perfect thanks for that, I’m hoping to use abs ( if I can get it to print without any warping ) so I’ll just do 100% infill on all the parts that will take any stress, thanks again!

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Camo77Ashlylong1990

Reply 8 weeks ago

Yes abs would be good but I can never get it to print right on larger parts. I have a heated bed, enclosure, just need some time to get it right

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Ashlylong1990Camo77

Reply 8 weeks ago

I’m the same, it’s the warping for me, out of curiosity has your pla+ help up? And do you know what fps your getting from the airsoft gun? Thanks :)