Behold, The Brilliantly Easy to Assemble Shooty Thing (or BEAST). This project is intended to be a compact, close-range, single-shot, backup, easy to manufacture weapon.
Unfortunately, Because of where I live, I cannot print or test-fire this gun, so...
This is an untested design. I am publishing it for free so that the community can give me the issues with the design and I can rework it. Any fees you might pay have not come from me.
If you have a low resolution printer, it might be a good idea to sand some parts of the gun so that they'll have some clearance when they slide past each other.
Once this model IS perfected, it will continue to be free.
The OBJ file is here, as well as several STL files. Use the "guide" picture files to know what part is what.
You should find assembly easy (since it is the Brilliantly Easy to Assemble Shooty Thing), but I will tell you the steps anyway:
drop the mag block into the long mag section and put some sort of spring down there.
Slide on the mag heel, and glue it if you want.
insert the mag lock (with a spring on the larger column) into it's hole and add a small screw (via the small hole near it) to prevent it popping out.
Insert a length of metal pipe for the barrel that will accommodate a .22 caliber bullet. This can be any length desired.
Place the Ejector on the column that sticks up at a 70-degree angle near the loading-end of the barrel. then attach an extension spring that links to the odd looking bit and to the ejector. this should keep the ejector oriented lengthwise to the Chassis.
Insert the Trigger into it's proper spot using the trigger pivot as a pivot [sic] and the rectangular beam into the rectangular hole behind it.
Use a screw to attach them at the pivot-hole.
In the oddly-shaped cavity in the handle, insert the Hammer-Release Pin to its hole and slide the Hammer Release onto its Pin.
Add one of those small "loom" elastics to keep the Hammer-Release in the forward position and slide the Mechanism Cover into place, fastening it with the Mech Cover Pin.
[At this point the trigger should spring back to the ready position after it has been squeezed.]
Insert a torsion spring into the Hammer (The torsion spring should have a pressing strength of around 907g in order to fire the round and you may have to enlarge the holes for the legs of the spring to fit in) making sure to insert one of the legs into the provided hole in the Chassis.
Put a compression spring into the channel on top of the barrel-holder bit.
Use a nail as a firing-pin: slip it into the hole in the back end of the slide.
put the slide onto the chassis.
put some shooters in the magazine.
Put the magazine into the Shooty Thing.
Test fire it and tell me improvements.
Do me a favour and right after you fire it, IF the slide blows back, pull the trigger again to see if it ends up being semi-automatic. If not, it doesn't matter.