Bolt Action Hand Cannon (100% 3D Printed!)

My Hand Cannon is a fully 3D printable spring powered projectile launcher. Based off torsion spring technology, this launcher is incredibly powerful, launching ammo up to 20 feet! The model is designed to be held in the left hand, and the pin can be pulled back with the thumb or other hand. Ammo is loaded down the main barrel and launched!

Print materials:

The ammo, cover and main body can be printed in whatever material you like best. I only tested PLA basic and PLA Matte, but it should be fine in other materials. Print the torsion spring with PLA Basic for best spring power! PLA Matte does not have the same stiffness as basic, and PETG is too flexible. I tested white overture PLA Basic and bambu black PLA Basic and both worked great.

Assembly:

The model is split up into two plates. All the parts do fit on one, but I was having bed adhesion problems printing the spring with the large body pieces, so I've spit them up to avoid that. If you still have bed adhesion issues, try washing your print plate with soap and warm water. It did the trick for me.

First, the spring is inserted into the cross-shaped hole in the middle of the main body's circle cavity. The peg should fit just right into the hole. Tighten the spring and push the long, circular peg into the slot around the perimeter of the circular cavity. It should look like this:

Now, place in cover on top of the spring. It seems to fit best with the printer-bed side down (inserted first). This is a tighter fit and prevents the circular cover from falling out. If it does fall out, try the other way.

The launcher is now assembled! Ammo (provided) is loaded down the barrel. To fire, angle the launcher a few degrees above horizontal (to prevent the ammo from falling out), pull the spring back and around, and release. The further you pull the spring back, the harder the ammo will shoot. 

Other:

If left in the casing for long enough, the spring will eventually deform and lose stiffness. This will result in a loss of power. To avoid this issue, remove the spring from the launcher when not in use to extend its lifetime. When the spring eventually does lose its power, you could try using a heat gun to bring the spring back to its original shape, but I usually just print another one because they're so small.

I sometimes had some problems with loose lines at the very back of the barrel, right where the pin hits the ammo. It was stopping the pin early and not allowing the pin to hit the projectiles right. I was able to trim it in about 10 seconds just with a small knife and the launcher worked great after that quick fix.

Sometimes the spring needs a little wear before it moves smoothly. Play with it a few times and it should become smoother.

Disclaimer: Don't shoot people in the eye :) It doesn't shoot as hard as a bb gun, but it would still hurt if it hit you directly in the eye.

If you want to see upgrades or modifications, feel free to like, comment or boost! If the model is received well, I'll put more time into making other versions.