This isn't 100% homemade, this is kinda borderline mod/homemade territory, so move this if necessary.
Basically, I had a barricade which sucked, and I wanted to take its little flywheel system and turn it into a machine gun. Shoving darts down a funnel into it didn't work, so I decided that a shotgun would have to do. Its name comes from the fact that there is only one sound that is naturally produced which is more irritating than the buzzing of a barricade. That sound is made by a cicada.
Like all of my other guns I've made so far, this thing was put together using scraps of PVC I had lying around, plus other nerf gun parts. (In fact, I haven't bought any PVC at all- the PVC I've been using for the past three months was bought by my cousin when he visited. He bought like 6' of PVC.) I used a few inches of 3/4" PVC, a couple feet of 1/2" PVC, an inch of 1" PVC, some bolts, a spring, the cardboard rod from a coat hanger, the barricade front assembly, and some other random crap. It took me like five minutes to slap together. The dart chamber and bolt sleeve are 1/2" PVC, and all the external parts are 3/4" PVC. The 1" PVC is used for a coupling for the motor assembly.
How does it work? A trigger, in the form of a momentary switch, turns on the noise generators. Cocking the gun is very similar to with any bolt action gun, except you don't push the bolt forwards after primed; rather, you rotate the bolt into a slot in the sleeve. Then, load the gun by rotating the front 3/4" cover and exposing the loading slot. You can fit 3 stock darts inside or 4-6 slugs/dome tops. Then close the cover. Just before firing, lift the safety with your thumb, then flick the bolt out of the notch to fire. Unconventional, yes, but very effective. If you want to only dispense of one or two darts, slide the bolt blocker into position (the rear 3/4" clip). This is a work in progress and I have yet to determine the exact locations you can set it at.
I already gave an overview of the assembly, but it's pretty simple and easy to figure out for yourself when you see it. Pics:
Rear bolt assembly and bolt sleeve, safe; shotgun setting.
Same shot, but with the dart control slide shut.
Close-up of the external spring and dart cover. The 3/4" PVC you see in the middle was just a coupler, because I didn't have any intact 2' sections of 1/2" PVC
Left-handed grip. The bent nail is a safety to prevent the darts from vibrating into the motors prematurely. Lift it with your thumb. Right-handed grip is pretty much the same.
Grip from right side
Front view. Notice that the gearbox has been reversed from its orientation in the barricade.
Bottom view.
Darts kept on getting caught in this edge, causing massive jams, so I sanded it down.
Dart door, removed.
Dart door, removed, showing spring and bolt.
Dart door open, loading slot.
ExplanationsFor the 3/4" PVC sliding/rotating parts, I cut a quarter of the pipe off so the 3 quarters left can snap easily over the 1/2" PVC.
The external spring serves to push the darts into the motors. It does not launch the darts, although without the gearbox attached, the spring can shoot the darts 10-20 ft.
Ranges:
With stock (streamline) darts, this gets about 60 ft. If you shoot three darts, they typically have a horizontal spread and land about 2-3' apart.
With my own domed slugs, I got 50'. Other slugs would probably work better because mine use 3/8" tips and wider ones catch the gears more. 1/2" domes don't work because they can't compress to fit through the gears, and they end up going through at an angle which makes them fishtail automatically.
1/2" PVC doesn't support whistler dart use, although I would expect 70' ranges with those if I had made the chamber out of something a little wider. The wider tips tend to really catch the flywheels and they go flying.
All ranges for PTG firing.
Future additions:
If anyone wants to replicate this, there are a few things that I would do.
First, use a wider chamber material, because the 1/2" PVC does not fit whistler darts.
Second, use a longer chamber/bolt sleeve because you can fit more darts in it.
Third, use a compression spring and cap the bolt sleeve, so no external springs can get caught on anything or make the gun "stutter".
Fourth, use a wooden dowel for the dart rod, instead of cardboard. Cardboard should not be used for nerf guns. It falls apart.
Fifth, use a barrel. I didn't feel like inhaling all the extra PVC dust from sanding a barrel down, but I would use Sch. 80 PVC and then sand out the inside so the darts are funneled into it.
That is all. Flames/comments/questions?