So about a week ago I started brainstorming ideas for a nerf gun to make and i decided to make a shotgun. I then decided i wanted it to use shells and be spring powered, so i got to work and this is what i came up with. Ill let the pictures explain the method I am using to load and eject the shells...
This is what breach system looks like. There would normally be a barrel in front of it and the plunger rod/spring behind it, but I excluded those parts and others for the sake of simplicity in demonstrating how it works.
The pieces below the cpvc tube (copper) when functioning are actually in the pipe held by the set screws above the cpvc pipe (grey). The charging handle would normally be attached to the cpvc pipe. Keep in mind, all of these parts are inside of a piece of 1" piece of pvc pipe when the gun is actually functioning.
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The Charging handle is pulled back and the breach looks like the above picture(the spring is compressed at the same time). A shell falls in from the feed tube (not shown) as the slot in the cpvc (grey) aligns with a corresponding slot in the main body of the gun.
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The pieces of copper will look like they are in the above image (excluding the cpvc shroud). The middle piece of copper is the shell (which would have a stefan in it).
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As the charging handle slams forward the piece of copper on the right will begin to push the shell into the forward breach chamber.
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When the charging handle comes to rest in its furthest forward postion, all of the breach compnents will look like they do in the above picture.
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This is the same as the above picture, except the cpvc shroud is included. The charging handle is in the same position. At this point the gun is completely primed and ready to be fired. Once the gun is fired, to reprime it, the charging handle is pulled back and the shell falls out of the foward slot in the piece of copper as the piece of cpvc uncovers it.
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So now you hopefully understand my breach/loading system, so heres my plunger assembly. Its somewhat beaten up from lots of firing though and i need to remake it with better materials so it won't fall apart again. Other than that it works fine, it has an excellent friction to seal ratio and is somewhat light weight.
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Here's a picture of my fire control group. As the trigger slides backwards the wheel collar slides down along the rails i made of sheet metal rivited together, which all together forces the firing pin down.
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And here is a picture of all of the parts to the gun.
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One thing i like about this gun is that shells take roughly 10 seconds to make each, so it makes things convenient as i dont really have to worry about losing any.
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So at this point your probably wondering, "What the hell does this thing look like?". Well, you're just going to have to wait, as i took two pieces apart for pictures and forgot to teflon tape them together properly so they pulled apart. Tomorrow hopefully ill get around to dismantling the gun again and taping up the parts so they're airtight/ taking some pictures. Also i dremeled the clearances for the breach parts wrong, so i cant get any stats untill i remake the breach as all of the air generated from the plunger goes strait out of a 1/8" long slit in between two parts. this wouldnt be a big deal, but i dont have any spare 12"x1/2" copper repair couplers at the moment and alot of hardware stores tend to not carry them. On the bright side the gun can cycle shells perfectly and fire fine, it just cant fire anything yet.
Torque
Member Since 30 Mar 2006Offline Last Active Oct 20 2010 02:19 PM