3D Printed 2/3 scale M16 Model Gun

Designed from scratch in software and 3D printed using PETG filament on an Ender 3. PETG is a pain to print sometimes and as you can see, the surface finish in various places is pretty crappy. Obviously, springs and pins and various bits like the extractor are metal. Using Marushin 9mm blowback cartridges. It feeds and ejects 90% of the time but could benefit from a stronger recoil spring and more bolt mass.

Once I buy more caps, I intend to make this cap firing while gradually improving cosmetics. It's 2/3 scale because 3D printing takes aaaaaages and this is just a prototype.

Nice work, we have all thought if 3d printing could help with spare parts but so far the 3d plastic has been too weak for the violent ation on blowback. It will be interesting to see how yours stands up to firing caps.

I'm very impressed you got this far

I could print small things with PETG but larger ones went banana shaped.

Looking good.

8ace

Thank you both for the replies!
@Claymore
Thank you and that's very true. This type of 3D printing will always be weaker than injection moulding but I have found printing "against the grain" (basically where stress is likely to be applied) can help make parts stronger. Soaking parts with a layer of super glue also seems to work too though it can get messy, hence why the surface finish looks rough. The main area that I will have to reinforce on this is the chamber and upper receiver takedown pin bits. Originally, I was copying the old model MGC M16 for the firing mechanism where the buffer is actually the striker/hammer but getting it to work on a small scale was tricky. So, instead I am going to copy the Tanio Koba M4 design which I believe is centre fire.

@8ace
Thank you! I know very much what you mean about PETG going banana shaped, you can see the warping on my model around the underside of the handguard. I still haven't figured out how to properly print large parts in PETG without warping. Like you said, I have the most success with PETG for small parts. PLA is weaker but is much easier to work with so I tend to use that for larger parts where the greater thickness add strength.

Wow! Just got a 3D printer myself and just yesterday started work on a P90 model. What resources did you use for modeling? (Also are you willing to share those files?)